No caller cares about the return value of create_object(), so make it
return void.

Link: https://lkml.kernel.org/r/20220901023007.3471887-1-liushixin2@huawei.comSigned-off-by: NLiu Shixin <liushixin2@huawei.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

The first RCU-based object iteration loop has to modify the object count. 
So we cannot skip taking the object lock.

One way to avoid soft lockup is to insert occasional cond_resched() call
into the loop.  This cannot be done while holding the RCU read lock which
is to protect objects from being freed.  However, taking a reference to
the object will prevent it from being freed.  We can then do a
cond_resched() call after every 64k objects safely.

Link: https://lkml.kernel.org/r/20220614220359.59282-4-longman@redhat.comSigned-off-by: NWaiman Long <longman@redhat.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

There are 3 RCU-based object iteration loops in kmemleak_scan().  Because
of the need to take RCU read lock, we can't insert cond_resched() into the
loop like other parts of the function.  As there can be millions of
objects to be scanned, it takes a while to iterate all of them.  The
kmemleak functionality is usually enabled in a debug kernel which is much
slower than a non-debug kernel.  With sufficient number of kmemleak
objects, the time to iterate them all may exceed 22s causing soft lockup.

  watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [kmemleak:625]

In this particular bug report, the soft lockup happen in the 2nd iteration
loop.

In the 2nd and 3rd loops, most of the objects are checked and then skipped
under the object lock.  Only a selected fews are modified.  Those objects
certainly need lock protection.  However, the lock/unlock operation is
slow especially with interrupt disabling and enabling included.

We can actually do some basic check like color_white() without taking the
lock and skip the object accordingly.  Of course, this kind of check is
racy and may miss objects that are being modified concurrently.  The cost
of missed objects, however, is just that they will be discovered in the
next scan instead.  The advantage of doing so is that iteration can be
done much faster especially with LOCKDEP enabled in a debug kernel.

With a debug kernel running on a 2-socket 96-thread x86-64 system
(HZ=1000), the 2nd and 3rd iteration loops speedup with this patch on the
first kmemleak_scan() call after bootup is shown in the table below.

                   Before patch                    After patch
  Loop #    # of objects  Elapsed time     # of objects  Elapsed time
  ------    ------------  ------------     ------------  ------------
    2        2,599,850      2.392s          2,596,364       0.266s
    3        2,600,176      2.171s          2,597,061       0.260s

This patch reduces loop iteration times by about 88%.  This will greatly
reduce the chance of a soft lockup happening in the 2nd or 3rd iteration
loops.

Even though the first loop runs a little bit faster, it can still be
problematic if many kmemleak objects are there.  As the object count has
to be modified in every object, we cannot avoid taking the object lock. 
So other way to prevent soft lockup will be needed.

Link: https://lkml.kernel.org/r/20220614220359.59282-3-longman@redhat.comSigned-off-by: NWaiman Long <longman@redhat.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Patch series "mm/kmemleak: Avoid soft lockup in kmemleak_scan()", v2.

There are 3 RCU-based object iteration loops in kmemleak_scan().  Because
of the need to take RCU read lock, we can't insert cond_resched() into the
loop like other parts of the function.  As there can be millions of
objects to be scanned, it takes a while to iterate all of them.  The
kmemleak functionality is usually enabled in a debug kernel which is much
slower than a non-debug kernel.  With sufficient number of kmemleak
objects, the time to iterate them all may exceed 22s causing soft lockup.

  watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [kmemleak:625]

This patch series make changes to the 3 object iteration loops in
kmemleak_scan() to prevent them from causing soft lockup.


This patch (of 3):

kmemleak_scan() is called only from the kmemleak scan thread or from write
to the kmemleak debugfs file.  Both are in task context and so we can
directly use the simpler _irq() lock/unlock calls instead of the more
complex _irqsave/_irqrestore variants.

Similarly, kmemleak_clear() is called only from write to the kmemleak
debugfs file. The same change can be applied.

Link: https://lkml.kernel.org/r/20220614220359.59282-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20220614220359.59282-2-longman@redhat.comSigned-off-by: NWaiman Long <longman@redhat.com>
Reviewed-by: NMuchun Song <songmuchun@bytedance.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Check the physical address of objects for its boundary when scan instead
of in kmemleak_*_phys().

Link: https://lkml.kernel.org/r/20220611035551.1823303-5-patrick.wang.shcn@gmail.com
Fixes: 23c2d497 ("mm: kmemleak: take a full lowmem check in kmemleak_*_phys()")
Signed-off-by: NPatrick Wang <patrick.wang.shcn@gmail.com>
Suggested-by: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Yee Lee <yee.lee@mediatek.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Add object_phys_tree_root to store the objects allocated with physical
address.  Distinguish it from object_tree_root by OBJECT_PHYS flag or
function argument.  The physical address is stored directly in those
objects.

Link: https://lkml.kernel.org/r/20220611035551.1823303-4-patrick.wang.shcn@gmail.comSigned-off-by: NPatrick Wang <patrick.wang.shcn@gmail.com>
Suggested-by: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Yee Lee <yee.lee@mediatek.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Add OBJECT_PHYS flag for object.  This flag is used to identify the
objects allocated with physical address.  The create_object_phys()
function is added as well to set that flag and is used by
kmemleak_alloc_phys().

Link: https://lkml.kernel.org/r/20220611035551.1823303-3-patrick.wang.shcn@gmail.comSigned-off-by: NPatrick Wang <patrick.wang.shcn@gmail.com>
Suggested-by: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Yee Lee <yee.lee@mediatek.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Patch series "mm: kmemleak: store objects allocated with physical address
separately and check when scan", v4.

The kmemleak_*_phys() interface uses "min_low_pfn" and "max_low_pfn" to
check address.  But on some architectures, kmemleak_*_phys() is called
before those two variables initialized.  The following steps will be
taken:

1) Add OBJECT_PHYS flag and rbtree for the objects allocated
   with physical address
2) Store physical address in objects if allocated with OBJECT_PHYS
3) Check the boundary when scan instead of in kmemleak_*_phys()

This patch set will solve:
https://lore.kernel.org/r/20220527032504.30341-1-yee.lee@mediatek.com
https://lore.kernel.org/r/9dd08bb5-f39e-53d8-f88d-bec598a08c93@gmail.com

v3: https://lore.kernel.org/r/20220609124950.1694394-1-patrick.wang.shcn@gmail.com
v2: https://lore.kernel.org/r/20220603035415.1243913-1-patrick.wang.shcn@gmail.com
v1: https://lore.kernel.org/r/20220531150823.1004101-1-patrick.wang.shcn@gmail.com


This patch (of 4):

Remove the unused kmemleak_not_leak_phys() function.  And remove the
min_count argument to kmemleak_alloc_phys() function, assume it's 0.

Link: https://lkml.kernel.org/r/20220611035551.1823303-1-patrick.wang.shcn@gmail.com
Link: https://lkml.kernel.org/r/20220611035551.1823303-2-patrick.wang.shcn@gmail.comSigned-off-by: NPatrick Wang <patrick.wang.shcn@gmail.com>
Suggested-by: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Yee Lee <yee.lee@mediatek.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

The kmemleak_*_phys() apis do not check the address for lowmem's min
boundary, while the caller may pass an address below lowmem, which will
trigger an oops:

  # echo scan > /sys/kernel/debug/kmemleak
  Unable to handle kernel paging request at virtual address ff5fffffffe00000
  Oops [#1]
  Modules linked in:
  CPU: 2 PID: 134 Comm: bash Not tainted 5.18.0-rc1-next-20220407 #33
  Hardware name: riscv-virtio,qemu (DT)
  epc : scan_block+0x74/0x15c
   ra : scan_block+0x72/0x15c
  epc : ffffffff801e5806 ra : ffffffff801e5804 sp : ff200000104abc30
   gp : ffffffff815cd4e8 tp : ff60000004cfa340 t0 : 0000000000000200
   t1 : 00aaaaaac23954cc t2 : 00000000000003ff s0 : ff200000104abc90
   s1 : ffffffff81b0ff28 a0 : 0000000000000000 a1 : ff5fffffffe01000
   a2 : ffffffff81b0ff28 a3 : 0000000000000002 a4 : 0000000000000001
   a5 : 0000000000000000 a6 : ff200000104abd7c a7 : 0000000000000005
   s2 : ff5fffffffe00ff9 s3 : ffffffff815cd998 s4 : ffffffff815d0e90
   s5 : ffffffff81b0ff28 s6 : 0000000000000020 s7 : ffffffff815d0eb0
   s8 : ffffffffffffffff s9 : ff5fffffffe00000 s10: ff5fffffffe01000
   s11: 0000000000000022 t3 : 00ffffffaa17db4c t4 : 000000000000000f
   t5 : 0000000000000001 t6 : 0000000000000000
  status: 0000000000000100 badaddr: ff5fffffffe00000 cause: 000000000000000d
    scan_gray_list+0x12e/0x1a6
    kmemleak_scan+0x2aa/0x57e
    kmemleak_write+0x32a/0x40c
    full_proxy_write+0x56/0x82
    vfs_write+0xa6/0x2a6
    ksys_write+0x6c/0xe2
    sys_write+0x22/0x2a
    ret_from_syscall+0x0/0x2

The callers may not quite know the actual address they pass(e.g. from
devicetree).  So the kmemleak_*_phys() apis should guarantee the address
they finally use is in lowmem range, so check the address for lowmem's
min boundary.

Link: https://lkml.kernel.org/r/20220413122925.33856-1-patrick.wang.shcn@gmail.comSigned-off-by: NPatrick Wang <patrick.wang.shcn@gmail.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we use HW-tag based kasan and enable vmalloc support, we hit the
following bug.  It is due to comparison between tagged object and
non-tagged pointer.

We need to reset the kasan tag when we need to compare tagged object and
non-tagged pointer.

  kmemleak: [name:kmemleak&]Scan area larger than object 0xffffffe77076f440
  CPU: 4 PID: 1 Comm: init Tainted: G S      W         5.15.25-android13-0-g5cacf919c2bc #1
  Hardware name: MT6983(ENG) (DT)
  Call trace:
   add_scan_area+0xc4/0x244
   kmemleak_scan_area+0x40/0x9c
   layout_and_allocate+0x1e8/0x288
   load_module+0x2c8/0xf00
   __se_sys_finit_module+0x190/0x1d0
   __arm64_sys_finit_module+0x20/0x30
   invoke_syscall+0x60/0x170
   el0_svc_common+0xc8/0x114
   do_el0_svc+0x28/0xa0
   el0_svc+0x60/0xf8
   el0t_64_sync_handler+0x88/0xec
   el0t_64_sync+0x1b4/0x1b8
  kmemleak: [name:kmemleak&]Object 0xf5ffffe77076b000 (size 32768):
  kmemleak: [name:kmemleak&]  comm "init", pid 1, jiffies 4294894197
  kmemleak: [name:kmemleak&]  min_count = 0
  kmemleak: [name:kmemleak&]  count = 0
  kmemleak: [name:kmemleak&]  flags = 0x1
  kmemleak: [name:kmemleak&]  checksum = 0
  kmemleak: [name:kmemleak&]  backtrace:
       module_alloc+0x9c/0x120
       move_module+0x34/0x19c
       layout_and_allocate+0x1c4/0x288
       load_module+0x2c8/0xf00
       __se_sys_finit_module+0x190/0x1d0
       __arm64_sys_finit_module+0x20/0x30
       invoke_syscall+0x60/0x170
       el0_svc_common+0xc8/0x114
       do_el0_svc+0x28/0xa0
       el0_svc+0x60/0xf8
       el0t_64_sync_handler+0x88/0xec
       el0t_64_sync+0x1b4/0x1b8

Link: https://lkml.kernel.org/r/20220318034051.30687-1-Kuan-Ying.Lee@mediatek.comSigned-off-by: NKuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Nicholas Tang <nicholas.tang@mediatek.com>
Cc: Yee Lee <yee.lee@mediatek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When using devm_request_free_mem_region() and devm_memremap_pages() to
add ZONE_DEVICE memory, if requested free mem region's end pfn were
huge(e.g., 0x400000000), the node_end_pfn() will be also huge (see
move_pfn_range_to_zone()).  Thus it creates a huge hole between
node_start_pfn() and node_end_pfn().

We found on some AMD APUs, amdkfd requested such a free mem region and
created a huge hole.  In such a case, following code snippet was just
doing busy test_bit() looping on the huge hole.

  for (pfn = start_pfn; pfn < end_pfn; pfn++) {
	struct page *page = pfn_to_online_page(pfn);
		if (!page)
			continue;
	...
  }

So we got a soft lockup:

  watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
  CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
  RIP: 0010:pfn_to_online_page+0x5/0xd0
  Call Trace:
    ? kmemleak_scan+0x16a/0x440
    kmemleak_write+0x306/0x3a0
    ? common_file_perm+0x72/0x170
    full_proxy_write+0x5c/0x90
    vfs_write+0xb9/0x260
    ksys_write+0x67/0xe0
    __x64_sys_write+0x1a/0x20
    do_syscall_64+0x3b/0xc0
    entry_SYSCALL_64_after_hwframe+0x44/0xae

I did some tests with the patch.

(1) amdgpu module unloaded

before the patch:

  real    0m0.976s
  user    0m0.000s
  sys     0m0.968s

after the patch:

  real    0m0.981s
  user    0m0.000s
  sys     0m0.973s

(2) amdgpu module loaded

before the patch:

  real    0m35.365s
  user    0m0.000s
  sys     0m35.354s

after the patch:

  real    0m1.049s
  user    0m0.000s
  sys     0m1.042s

Link: https://lkml.kernel.org/r/20211108140029.721144-1-lang.yu@amd.comSigned-off-by: NLang Yu <lang.yu@amd.com>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With HW tag-based kasan enable, We will get the warning when we free
object whose address starts with 0xFF.

It is because kmemleak rbtree stores tagged object and this freeing
object's tag does not match with rbtree object.

In the example below, kmemleak rbtree stores the tagged object in the
kmalloc(), and kfree() gets the pointer with 0xFF tag.

Call sequence:
    ptr = kmalloc(size, GFP_KERNEL);
    page = virt_to_page(ptr);
    offset = offset_in_page(ptr);
    kfree(page_address(page) + offset);
    ptr = kmalloc(size, GFP_KERNEL);

A sequence like that may cause the warning as following:

 1) Freeing unknown object:

    In kfree(), we will get free unknown object warning in
    kmemleak_free(). Because object(0xFx) in kmemleak rbtree and
    pointer(0xFF) in kfree() have different tag.

 2) Overlap existing:

    When we allocate that object with the same hw-tag again, we will
    find the overlap in the kmemleak rbtree and kmemleak thread will be
    killed.

	kmemleak: Freeing unknown object at 0xffff000003f88000
	CPU: 5 PID: 177 Comm: cat Not tainted 5.16.0-rc1-dirty #21
	Hardware name: linux,dummy-virt (DT)
	Call trace:
	 dump_backtrace+0x0/0x1ac
	 show_stack+0x1c/0x30
	 dump_stack_lvl+0x68/0x84
	 dump_stack+0x1c/0x38
	 kmemleak_free+0x6c/0x70
	 slab_free_freelist_hook+0x104/0x200
	 kmem_cache_free+0xa8/0x3d4
	 test_version_show+0x270/0x3a0
	 module_attr_show+0x28/0x40
	 sysfs_kf_seq_show+0xb0/0x130
	 kernfs_seq_show+0x30/0x40
	 seq_read_iter+0x1bc/0x4b0
	 seq_read_iter+0x1bc/0x4b0
	 kernfs_fop_read_iter+0x144/0x1c0
	 generic_file_splice_read+0xd0/0x184
	 do_splice_to+0x90/0xe0
	 splice_direct_to_actor+0xb8/0x250
	 do_splice_direct+0x88/0xd4
	 do_sendfile+0x2b0/0x344
	 __arm64_sys_sendfile64+0x164/0x16c
	 invoke_syscall+0x48/0x114
	 el0_svc_common.constprop.0+0x44/0xec
	 do_el0_svc+0x74/0x90
	 el0_svc+0x20/0x80
	 el0t_64_sync_handler+0x1a8/0x1b0
	 el0t_64_sync+0x1ac/0x1b0
	...
	kmemleak: Cannot insert 0xf2ff000003f88000 into the object search tree (overlaps existing)
	CPU: 5 PID: 178 Comm: cat Not tainted 5.16.0-rc1-dirty #21
	Hardware name: linux,dummy-virt (DT)
	Call trace:
	 dump_backtrace+0x0/0x1ac
	 show_stack+0x1c/0x30
	 dump_stack_lvl+0x68/0x84
	 dump_stack+0x1c/0x38
	 create_object.isra.0+0x2d8/0x2fc
	 kmemleak_alloc+0x34/0x40
	 kmem_cache_alloc+0x23c/0x2f0
	 test_version_show+0x1fc/0x3a0
	 module_attr_show+0x28/0x40
	 sysfs_kf_seq_show+0xb0/0x130
	 kernfs_seq_show+0x30/0x40
	 seq_read_iter+0x1bc/0x4b0
	 kernfs_fop_read_iter+0x144/0x1c0
	 generic_file_splice_read+0xd0/0x184
	 do_splice_to+0x90/0xe0
	 splice_direct_to_actor+0xb8/0x250
	 do_splice_direct+0x88/0xd4
	 do_sendfile+0x2b0/0x344
	 __arm64_sys_sendfile64+0x164/0x16c
	 invoke_syscall+0x48/0x114
	 el0_svc_common.constprop.0+0x44/0xec
	 do_el0_svc+0x74/0x90
	 el0_svc+0x20/0x80
	 el0t_64_sync_handler+0x1a8/0x1b0
	 el0t_64_sync+0x1ac/0x1b0
	kmemleak: Kernel memory leak detector disabled
	kmemleak: Object 0xf2ff000003f88000 (size 128):
	kmemleak:   comm "cat", pid 177, jiffies 4294921177
	kmemleak:   min_count = 1
	kmemleak:   count = 0
	kmemleak:   flags = 0x1
	kmemleak:   checksum = 0
	kmemleak:   backtrace:
	     kmem_cache_alloc+0x23c/0x2f0
	     test_version_show+0x1fc/0x3a0
	     module_attr_show+0x28/0x40
	     sysfs_kf_seq_show+0xb0/0x130
	     kernfs_seq_show+0x30/0x40
	     seq_read_iter+0x1bc/0x4b0
	     kernfs_fop_read_iter+0x144/0x1c0
	     generic_file_splice_read+0xd0/0x184
	     do_splice_to+0x90/0xe0
	     splice_direct_to_actor+0xb8/0x250
	     do_splice_direct+0x88/0xd4
	     do_sendfile+0x2b0/0x344
	     __arm64_sys_sendfile64+0x164/0x16c
	     invoke_syscall+0x48/0x114
	     el0_svc_common.constprop.0+0x44/0xec
	     do_el0_svc+0x74/0x90
	kmemleak: Automatic memory scanning thread ended

[akpm@linux-foundation.org: whitespace tweak]

Link: https://lkml.kernel.org/r/20211118054426.4123-1-Kuan-Ying.Lee@mediatek.comSigned-off-by: NKuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In a memory pressure situation, I'm seeing the lockdep WARNING below.
Actually, this is similar to a known false positive which is already
addressed by commit 6dcde60e ("xfs: more lockdep whackamole with
kmem_alloc*").

This warning still persists because it's not from kmalloc() itself but
from an allocation for kmemleak object.  While kmalloc() itself suppress
the warning with __GFP_NOLOCKDEP, gfp_kmemleak_mask() is dropping the
flag for the kmemleak's allocation.

Allow __GFP_NOLOCKDEP to be passed to kmemleak's allocation, so that the
warning for it is also suppressed.

  ======================================================
  WARNING: possible circular locking dependency detected
  5.14.0-rc7-BTRFS-ZNS+ #37 Not tainted
  ------------------------------------------------------
  kswapd0/288 is trying to acquire lock:
  ffff88825ab45df0 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0x8a/0x250

  but task is already holding lock:
  ffffffff848cc1e0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #1 (fs_reclaim){+.+.}-{0:0}:
         fs_reclaim_acquire+0x112/0x160
         kmem_cache_alloc+0x48/0x400
         create_object.isra.0+0x42/0xb10
         kmemleak_alloc+0x48/0x80
         __kmalloc+0x228/0x440
         kmem_alloc+0xd3/0x2b0
         kmem_alloc_large+0x5a/0x1c0
         xfs_attr_copy_value+0x112/0x190
         xfs_attr_shortform_getvalue+0x1fc/0x300
         xfs_attr_get_ilocked+0x125/0x170
         xfs_attr_get+0x329/0x450
         xfs_get_acl+0x18d/0x430
         get_acl.part.0+0xb6/0x1e0
         posix_acl_xattr_get+0x13a/0x230
         vfs_getxattr+0x21d/0x270
         getxattr+0x126/0x310
         __x64_sys_fgetxattr+0x1a6/0x2a0
         do_syscall_64+0x3b/0x90
         entry_SYSCALL_64_after_hwframe+0x44/0xae

  -> #0 (&xfs_nondir_ilock_class){++++}-{3:3}:
         __lock_acquire+0x2c0f/0x5a00
         lock_acquire+0x1a1/0x4b0
         down_read_nested+0x50/0x90
         xfs_ilock+0x8a/0x250
         xfs_can_free_eofblocks+0x34f/0x570
         xfs_inactive+0x411/0x520
         xfs_fs_destroy_inode+0x2c8/0x710
         destroy_inode+0xc5/0x1a0
         evict+0x444/0x620
         dispose_list+0xfe/0x1c0
         prune_icache_sb+0xdc/0x160
         super_cache_scan+0x31e/0x510
         do_shrink_slab+0x337/0x8e0
         shrink_slab+0x362/0x5c0
         shrink_node+0x7a7/0x1a40
         balance_pgdat+0x64e/0xfe0
         kswapd+0x590/0xa80
         kthread+0x38c/0x460
         ret_from_fork+0x22/0x30

  other info that might help us debug this:
   Possible unsafe locking scenario:
         CPU0                    CPU1
         ----                    ----
    lock(fs_reclaim);
                                 lock(&xfs_nondir_ilock_class);
                                 lock(fs_reclaim);
    lock(&xfs_nondir_ilock_class);

   *** DEADLOCK ***
  3 locks held by kswapd0/288:
   #0: ffffffff848cc1e0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
   #1: ffffffff848a08d8 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x269/0x5c0
   #2: ffff8881a7a820e8 (&type->s_umount_key#60){++++}-{3:3}, at: super_cache_scan+0x5a/0x510

Link: https://lkml.kernel.org/r/20210907055659.3182992-1-naohiro.aota@wdc.comSigned-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace the obsolete and ambiguos macro in_irq() with new macro
in_hardirq().

Link: https://lkml.kernel.org/r/20210813145245.86070-1-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[kmemleak]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "kasan, slub: reset tag when printing address", v3.

With hardware tag-based kasan enabled, we reset the tag when we access
metadata to avoid from false alarm.

This patch (of 2):

Kmemleak needs to scan kernel memory to check memory leak.  With hardware
tag-based kasan enabled, when it scans on the invalid slab and
dereference, the issue will occur as below.

Hardware tag-based KASAN doesn't use compiler instrumentation, we can not
use kasan_disable_current() to ignore tag check.

Based on the below report, there are 11 0xf7 granules, which amounts to
176 bytes, and the object is allocated from the kmalloc-256 cache.  So
when kmemleak accesses the last 256-176 bytes, it causes faults, as those
are marked with KASAN_KMALLOC_REDZONE == KASAN_TAG_INVALID == 0xfe.

Thus, we reset tags before accessing metadata to avoid from false positives.

  BUG: KASAN: out-of-bounds in scan_block+0x58/0x170
  Read at addr f7ff0000c0074eb0 by task kmemleak/138
  Pointer tag: [f7], memory tag: [fe]

  CPU: 7 PID: 138 Comm: kmemleak Not tainted 5.14.0-rc2-00001-g8cae8cd8-dirty #134
  Hardware name: linux,dummy-virt (DT)
  Call trace:
   dump_backtrace+0x0/0x1b0
   show_stack+0x1c/0x30
   dump_stack_lvl+0x68/0x84
   print_address_description+0x7c/0x2b4
   kasan_report+0x138/0x38c
   __do_kernel_fault+0x190/0x1c4
   do_tag_check_fault+0x78/0x90
   do_mem_abort+0x44/0xb4
   el1_abort+0x40/0x60
   el1h_64_sync_handler+0xb4/0xd0
   el1h_64_sync+0x78/0x7c
   scan_block+0x58/0x170
   scan_gray_list+0xdc/0x1a0
   kmemleak_scan+0x2ac/0x560
   kmemleak_scan_thread+0xb0/0xe0
   kthread+0x154/0x160
   ret_from_fork+0x10/0x18

  Allocated by task 0:
   kasan_save_stack+0x2c/0x60
   __kasan_kmalloc+0xec/0x104
   __kmalloc+0x224/0x3c4
   __register_sysctl_paths+0x200/0x290
   register_sysctl_table+0x2c/0x40
   sysctl_init+0x20/0x34
   proc_sys_init+0x3c/0x48
   proc_root_init+0x80/0x9c
   start_kernel+0x648/0x6a4
   __primary_switched+0xc0/0xc8

  Freed by task 0:
   kasan_save_stack+0x2c/0x60
   kasan_set_track+0x2c/0x40
   kasan_set_free_info+0x44/0x54
   ____kasan_slab_free.constprop.0+0x150/0x1b0
   __kasan_slab_free+0x14/0x20
   slab_free_freelist_hook+0xa4/0x1fc
   kfree+0x1e8/0x30c
   put_fs_context+0x124/0x220
   vfs_kern_mount.part.0+0x60/0xd4
   kern_mount+0x24/0x4c
   bdev_cache_init+0x70/0x9c
   vfs_caches_init+0xdc/0xf4
   start_kernel+0x638/0x6a4
   __primary_switched+0xc0/0xc8

  The buggy address belongs to the object at ffff0000c0074e00
   which belongs to the cache kmalloc-256 of size 256
  The buggy address is located 176 bytes inside of
   256-byte region [ffff0000c0074e00, ffff0000c0074f00)
  The buggy address belongs to the page:
  page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x100074
  head:(____ptrval____) order:2 compound_mapcount:0 compound_pincount:0
  flags: 0xbfffc0000010200(slab|head|node=0|zone=2|lastcpupid=0xffff|kasantag=0x0)
  raw: 0bfffc0000010200 0000000000000000 dead000000000122 f5ff0000c0002300
  raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff0000c0074c00: f0 f0 f0 f0 f0 f0 f0 f0 f0 fe fe fe fe fe fe fe
   ffff0000c0074d00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
  >ffff0000c0074e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 fe fe fe fe fe
                                                      ^
   ffff0000c0074f00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
   ffff0000c0075000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ==================================================================
  Disabling lock debugging due to kernel taint
  kmemleak: 181 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

Link: https://lkml.kernel.org/r/20210804090957.12393-1-Kuan-Ying.Lee@mediatek.com
Link: https://lkml.kernel.org/r/20210804090957.12393-2-Kuan-Ying.Lee@mediatek.comSigned-off-by: NKuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NAndrey Konovalov <andreyknvl@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: Nicholas Tang <nicholas.tang@mediatek.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This commit contains 3 modifications:

1. Convert the type of jiffies_scan_wait to "unsigned long".

2. Use READ/WRITE_ONCE() for accessing "jiffies_scan_wait".

3. Fix the possible wrong memory scanning period.  If you set a large
   memory scanning period like blow, then the "secs" variable will be
   non-zero, however the value of "jiffies_scan_wait" will be zero.

    echo "scan=0x10000000" > /sys/kernel/debug/kmemleak

It is because the type of the msecs_to_jiffies()'s parameter is "unsigned
int", and the "secs * 1000" is larger than its max value.  This in turn
leads a unexpected jiffies_scan_wait, maybe zero.  We corret it by
replacing kstrtoul() with kstrtouint(), and check the msecs to prevent it
larger than UINT_MAX.

Link: https://lkml.kernel.org/r/20210613174022.23044-1-yanfei.xu@windriver.comSigned-off-by: NYanfei Xu <yanfei.xu@windriver.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

s/interruptable/interruptible/

Link: https://lkml.kernel.org/r/20210319214140.23304-1-unixbhaskar@gmail.comSigned-off-by: NBhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Because memblock allocations are registered with kmemleak, the KFENCE
pool was seen by kmemleak as one large object.  Later allocations
through kfence_alloc() that were registered with kmemleak via
slab_post_alloc_hook() would then overlap and trigger a warning.
Therefore, once the pool is initialized, we can remove (free) it from
kmemleak again, since it should be treated as allocator-internal and be
seen as "free memory".

The second problem is that kmemleak is passed the rounded size, and not
the originally requested size, which is also the size of KFENCE objects.
To avoid kmemleak scanning past the end of an object and trigger a
KFENCE out-of-bounds error, fix the size if it is a KFENCE object.

For simplicity, to avoid a call to kfence_ksize() in
slab_post_alloc_hook() (and avoid new IS_ENABLED(CONFIG_DEBUG_KMEMLEAK)
guard), just call kfence_ksize() in mm/kmemleak.c:create_object().

Link: https://lkml.kernel.org/r/20210317084740.3099921-1-elver@google.comSigned-off-by: NMarco Elver <elver@google.com>
Reported-by: NLuis Henriques <lhenriques@suse.de>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Tested-by: NLuis Henriques <lhenriques@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kmemleak_scan() currently relies on the big tasklist_lock hammer to
stabilize iterating through the tasklist.  Instead, this patch proposes
simply using rcu along with the rcu-safe for_each_process_thread flavor
(without changing scan semantics), which doesn't make use of
next_thread/p->thread_group and thus cannot race with exit.  Furthermore,
any races with fork() and not seeing the new child should be benign as
it's not running yet and can also be detected by the next scan.

Avoiding the tasklist_lock could prove beneficial for performance
considering the scan operation is done periodically.  I have seen
improvements of 30%-ish when doing similar replacements on very
pathological microbenchmarks (ie stressing get/setpriority(2)).

However my main motivation is that it's one less user of the global
lock, something that Linus has long time wanted to see gone eventually
(if ever) even if the traditional fairness issues has been dealt with
now with qrwlocks.  Of course this is a very long ways ahead.  This
patch also kills another user of the deprecated tsk->thread_group.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NQian Cai <cai@lca.pw>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20200820203902.11308-1-dave@stgolabs.netSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Even if KCSAN is disabled for kmemleak, update_checksum() could still call
crc32() (which is outside of kmemleak.c) to dereference object->pointer.
Thus, the value of object->pointer could be accessed concurrently as
noticed by KCSAN,

 BUG: KCSAN: data-race in crc32_le_base / do_raw_spin_lock

 write to 0xffffb0ea683a7d50 of 4 bytes by task 23575 on cpu 12:
  do_raw_spin_lock+0x114/0x200
  debug_spin_lock_after at kernel/locking/spinlock_debug.c:91
  (inlined by) do_raw_spin_lock at kernel/locking/spinlock_debug.c:115
  _raw_spin_lock+0x40/0x50
  __handle_mm_fault+0xa9e/0xd00
  handle_mm_fault+0xfc/0x2f0
  do_page_fault+0x263/0x6f9
  page_fault+0x34/0x40

 read to 0xffffb0ea683a7d50 of 4 bytes by task 839 on cpu 60:
  crc32_le_base+0x67/0x350
  crc32_le_base+0x67/0x350:
  crc32_body at lib/crc32.c:106
  (inlined by) crc32_le_generic at lib/crc32.c:179
  (inlined by) crc32_le at lib/crc32.c:197
  kmemleak_scan+0x528/0xd90
  update_checksum at mm/kmemleak.c:1172
  (inlined by) kmemleak_scan at mm/kmemleak.c:1497
  kmemleak_scan_thread+0xcc/0xfa
  kthread+0x1e0/0x200
  ret_from_fork+0x27/0x50

If a shattered value was returned due to a data race, it will be corrected
in the next scan.  Thus, let KCSAN ignore all reads in the region to
silence KCSAN in case the write side is non-atomic.
Suggested-by: NMarco Elver <elver@google.com>
Signed-off-by: NQian Cai <cai@lca.pw>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMarco Elver <elver@google.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Link: http://lkml.kernel.org/r/20200317182754.2180-1-cai@lca.pwSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Clang warns:

  mm/kmemleak.c:1955:28: warning: array comparison always evaluates to a constant [-Wtautological-compare]
        if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
                                  ^
  mm/kmemleak.c:1955:60: warning: array comparison always evaluates to a constant [-Wtautological-compare]
        if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)

These are not true arrays, they are linker defined symbols, which are just
addresses.  Using the address of operator silences the warning and does
not change the resulting assembly with either clang/ld.lld or gcc/ld
(tested with diff + objdump -Dr).
Suggested-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NNathan Chancellor <natechancellor@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/895
Link: http://lkml.kernel.org/r/20200220051551.44000-1-natechancellor@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kmemleak_lock as a rwlock on RT can possibly be acquired in atomic
context which does work.

Since the kmemleak operation is performed in atomic context make it a
raw_spinlock_t so it can also be acquired on RT.  This is used for
debugging and is not enabled by default in a production like environment
(where performance/latency matters) so it makes sense to make it a
raw_spinlock_t instead trying to get rid of the atomic context.  Turn
also the kmemleak_object->lock into raw_spinlock_t which is acquired
(nested) while the kmemleak_lock is held.

The time spent in "echo scan > kmemleak" slightly improved on 64core box
with this patch applied after boot.

[bigeasy@linutronix.de: redo the description, update comments. Merge the individual bits:  He Zhe did the kmemleak_lock, Liu Haitao the ->lock and Yongxin Liu forwarded Liu's patch.]
Link: http://lkml.kernel.org/r/20191219170834.4tah3prf2gdothz4@linutronix.de
Link: https://lkml.kernel.org/r/20181218150744.GB20197@arrakis.emea.arm.com
Link: https://lkml.kernel.org/r/1542877459-144382-1-git-send-email-zhe.he@windriver.com
Link: https://lkml.kernel.org/r/20190927082230.34152-1-yongxin.liu@windriver.comSigned-off-by: NHe Zhe <zhe.he@windriver.com>
Signed-off-by: NLiu Haitao <haitao.liu@windriver.com>
Signed-off-by: NYongxin Liu <yongxin.liu@windriver.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In case of an error (e.g. memory pool too small), kmemleak disables
itself and cleans up the already allocated metadata objects. However, if
this happens early before the RCU callback mechanism is available,
put_object() skips call_rcu() and frees the object directly. This is not
safe with the RCU list traversal in __kmemleak_do_cleanup().

Change the list traversal in __kmemleak_do_cleanup() to
list_for_each_entry_safe() and remove the rcu_read_{lock,unlock} since
the kmemleak is already disabled at this point. In addition, avoid an
unnecessary metadata object rb-tree look-up since it already has the
struct kmemleak_object pointer.

Fixes: c5665868 ("mm: kmemleak: use the memory pool for early allocations")
Reported-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Reported-by: NMarc Dionne <marc.c.dionne@gmail.com>
Reported-by: NTed Ts'o <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The only way to obtain the current memory pool size for a running kernel
is to check the kernel config file which is inconvenient.  Record it in
the kernel messages.

[akpm@linux-foundation.org: s/memory pool size/memory pool/available/, per Catalin]
Link: http://lkml.kernel.org/r/1565809631-28933-1-git-send-email-cai@lca.pwSigned-off-by: NQian Cai <cai@lca.pw>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently kmemleak uses a static early_log buffer to trace all memory
allocation/freeing before the slab allocator is initialised.  Such early
log is replayed during kmemleak_init() to properly initialise the kmemleak
metadata for objects allocated up that point.  With a memory pool that
does not rely on the slab allocator, it is possible to skip this early log
entirely.

In order to remove the early logging, consider kmemleak_enabled == 1 by
default while the kmem_cache availability is checked directly on the
object_cache and scan_area_cache variables.  The RCU callback is only
invoked after object_cache has been initialised as we wouldn't have any
concurrent list traversal before this.

In order to reduce the number of callbacks before kmemleak is fully
initialised, move the kmemleak_init() call to mm_init().

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: remove WARN_ON(), per Catalin]
Link: http://lkml.kernel.org/r/20190812160642.52134-4-catalin.marinas@arm.comSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a memory pool for struct kmemleak_object in case the normal
kmem_cache_alloc() fails under the gfp constraints passed by the caller.
The mem_pool[] array size is currently fixed at 16000.

We are not using the existing mempool kernel API since this requires
the slab allocator to be available (for pool->elements allocation).  A
subsequent kmemleak patch will replace the static early log buffer with
the pool allocation introduced here and this functionality is required
to be available before the slab was initialised.

Link: http://lkml.kernel.org/r/20190812160642.52134-3-catalin.marinas@arm.comSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "mm: kmemleak: Use a memory pool for kmemleak object
allocations", v3.

Following the discussions on v2 of this patch(set) [1], this series takes
slightly different approach:

- it implements its own simple memory pool that does not rely on the
  slab allocator

- drops the early log buffer logic entirely since it can now allocate
  metadata from the memory pool directly before kmemleak is fully
  initialised

- CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE option is renamed to
  CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE

- moves the kmemleak_init() call earlier (mm_init())

- to avoid a separate memory pool for struct scan_area, it makes the
  tool robust when such allocations fail as scan areas are rather an
  optimisation

[1] http://lkml.kernel.org/r/20190727132334.9184-1-catalin.marinas@arm.com

This patch (of 3):

Object scan areas are an optimisation aimed to decrease the false
positives and slightly improve the scanning time of large objects known to
only have a few specific pointers.  If a struct scan_area fails to
allocate, kmemleak can still function normally by scanning the full
object.

Introduce an OBJECT_FULL_SCAN flag and mark objects as such when scan_area
allocation fails.

Link: http://lkml.kernel.org/r/20190812160642.52134-2-catalin.marinas@arm.comSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If an error occurs during kmemleak_init() (e.g.  kmem cache cannot be
created), kmemleak is disabled but kmemleak_early_log remains enabled.
Subsequently, when the .init.text section is freed, the log_early()
function no longer exists.  To avoid a page fault in such scenario,
ensure that kmemleak_disable() also disables early logging.

Link: http://lkml.kernel.org/r/20190731152302.42073-1-catalin.marinas@arm.comSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Reported-by: NQian Cai <cai@lca.pw>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When running ltp's oom test with kmemleak enabled, the below warning was
triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is
passed in:

  WARNING: CPU: 105 PID: 2138 at mm/page_alloc.c:4608 __alloc_pages_nodemask+0x1c31/0x1d50
  Modules linked in: loop dax_pmem dax_pmem_core ip_tables x_tables xfs virtio_net net_failover virtio_blk failover ata_generic virtio_pci virtio_ring virtio libata
  CPU: 105 PID: 2138 Comm: oom01 Not tainted 5.2.0-next-20190710+ #7
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
  RIP: 0010:__alloc_pages_nodemask+0x1c31/0x1d50
  ...
   kmemleak_alloc+0x4e/0xb0
   kmem_cache_alloc+0x2a7/0x3e0
   mempool_alloc_slab+0x2d/0x40
   mempool_alloc+0x118/0x2b0
   bio_alloc_bioset+0x19d/0x350
   get_swap_bio+0x80/0x230
   __swap_writepage+0x5ff/0xb20

The mempool_alloc_slab() clears __GFP_DIRECT_RECLAIM, however kmemleak
has __GFP_NOFAIL set all the time due to d9570ee3 ("kmemleak:
allow to coexist with fault injection").  But, it doesn't make any sense
to have __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM specified at the same
time.

According to the discussion on the mailing list, the commit should be
reverted for short term solution.  Catalin Marinas would follow up with
a better solution for longer term.

The failure rate of kmemleak metadata allocation may increase in some
circumstances, but this should be expected side effect.

Link: http://lkml.kernel.org/r/1563299431-111710-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: d9570ee3 ("kmemleak: allow to coexist with fault injection")
Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com>
Suggested-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

According to POSIX, EBUSY means that the "device or resource is busy", and
this can lead to people thinking that the file
`/sys/kernel/debug/kmemleak/` is somehow locked or being used by other
process.  Change this error code to a more appropriate one.

Link: http://lkml.kernel.org/r/20190612155231.19448-1-andrealmeid@collabora.comSigned-off-by: NAndré Almeida <andrealmeid@collabora.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

in_softirq() is a wrong predicate to check if we are in a softirq
context.  It also returns true if we have BH disabled, so objects are
falsely stamped with "softirq" comm.  The correct predicate is
in_serving_softirq().

If user does cat from /sys/kernel/debug/kmemleak previously they would
see this, which is clearly wrong, this is system call context (see the
comm):

unreferenced object 0xffff88805bd661c0 (size 64):
  comm "softirq", pid 0, jiffies 4294942959 (age 12.400s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 ff ff ff ff 00 00 00 00  ................
    00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
  backtrace:
    [<0000000007dcb30c>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<0000000007dcb30c>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<0000000007dcb30c>] slab_alloc mm/slab.c:3326 [inline]
    [<0000000007dcb30c>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<00000000969722b7>] kmalloc include/linux/slab.h:547 [inline]
    [<00000000969722b7>] kzalloc include/linux/slab.h:742 [inline]
    [<00000000969722b7>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline]
    [<00000000969722b7>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085
    [<00000000a4134b5f>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475
    [<00000000d20248ad>] do_ip_setsockopt.isra.0+0x19fe/0x1c00 net/ipv4/ip_sockglue.c:957
    [<000000003d367be7>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246
    [<000000003c7c76af>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616
    [<000000000c1aeb23>] sock_common_setsockopt+0x3e/0x50 net/core/sock.c:3130
    [<000000000157b92b>] __sys_setsockopt+0x9e/0x120 net/socket.c:2078
    [<00000000a9f3d058>] __do_sys_setsockopt net/socket.c:2089 [inline]
    [<00000000a9f3d058>] __se_sys_setsockopt net/socket.c:2086 [inline]
    [<00000000a9f3d058>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
    [<000000001b8da885>] do_syscall_64+0x7c/0x1a0 arch/x86/entry/common.c:301
    [<00000000ba770c62>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

now they will see this:

unreferenced object 0xffff88805413c800 (size 64):
  comm "syz-executor.4", pid 8960, jiffies 4294994003 (age 14.350s)
  hex dump (first 32 bytes):
    00 7a 8a 57 80 88 ff ff e0 00 00 01 00 00 00 00  .z.W............
    00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000c5d3be64>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<00000000c5d3be64>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<00000000c5d3be64>] slab_alloc mm/slab.c:3326 [inline]
    [<00000000c5d3be64>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<0000000023865be2>] kmalloc include/linux/slab.h:547 [inline]
    [<0000000023865be2>] kzalloc include/linux/slab.h:742 [inline]
    [<0000000023865be2>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline]
    [<0000000023865be2>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085
    [<000000003029a9d4>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475
    [<00000000ccd0a87c>] do_ip_setsockopt.isra.0+0x19fe/0x1c00 net/ipv4/ip_sockglue.c:957
    [<00000000a85a3785>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246
    [<00000000ec13c18d>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616
    [<0000000052d748e3>] sock_common_setsockopt+0x3e/0x50 net/core/sock.c:3130
    [<00000000512f1014>] __sys_setsockopt+0x9e/0x120 net/socket.c:2078
    [<00000000181758bc>] __do_sys_setsockopt net/socket.c:2089 [inline]
    [<00000000181758bc>] __se_sys_setsockopt net/socket.c:2086 [inline]
    [<00000000181758bc>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
    [<00000000d4b73623>] do_syscall_64+0x7c/0x1a0 arch/x86/entry/common.c:301
    [<00000000c1098bec>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Link: http://lkml.kernel.org/r/20190517171507.96046-1-dvyukov@gmail.comSigned-off-by: NDmitry Vyukov <dvyukov@google.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 59 temple place suite 330 boston ma 02111
  1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 136 file(s).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NAlexios Zavras <alexios.zavras@intel.com>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.384967451@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-mm@kvack.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace the indirection through struct stack_trace by using the storage
array based interfaces.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: linux-mm@kvack.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: linux-btrfs@vger.kernel.org
Cc: dm-devel@redhat.com
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: linux-arch@vger.kernel.org
Link: https://lkml.kernel.org/r/20190425094801.863716911@linutronix.de

The only references outside of the #ifdef have been removed, so now we
get a warning in non-SMP configurations:

  mm/kmemleak.c:1404:13: error: unused function 'scan_large_block' [-Werror,-Wunused-function]

Add a new #ifdef around it.

Link: http://lkml.kernel.org/r/20190416123148.3502045-1-arnd@arndb.de
Fixes: 298a32b1 ("kmemleak: powerpc: skip scanning holes in the .bss section")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 2d4f5671 ("KVM: PPC: Introduce kvm_tmp framework") adds
kvm_tmp[] into the .bss section and then free the rest of unused spaces
back to the page allocator.

kernel_init
  kvm_guest_init
    kvm_free_tmp
      free_reserved_area
        free_unref_page
          free_unref_page_prepare

With DEBUG_PAGEALLOC=y, it will unmap those pages from kernel.  As the
result, kmemleak scan will trigger a panic when it scans the .bss
section with unmapped pages.

This patch creates dedicated kmemleak objects for the .data, .bss and
potentially .data..ro_after_init sections to allow partial freeing via
the kmemleak_free_part() in the powerpc kvm_free_tmp() function.

Link: http://lkml.kernel.org/r/20190321171917.62049-1-catalin.marinas@arm.comSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Reported-by: NQian Cai <cai@lca.pw>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: NQian Cai <cai@lca.pw>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kmemleak keeps two global variables, min_addr and max_addr, which store
the range of valid (encountered by kmemleak) pointer values, which it
later uses to speed up pointer lookup when scanning blocks.

With tagged pointers this range will get bigger than it needs to be.  This
patch makes kmemleak untag pointers before saving them to min_addr and
max_addr and when performing a lookup.

Link: http://lkml.kernel.org/r/16e887d442986ab87fe87a755815ad92fa431a5f.1550066133.git.andreyknvl@google.comSigned-off-by: NAndrey Konovalov <andreyknvl@google.com>
Tested-by: NQian Cai <cai@lca.pw>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Kmemleak scan can be cpu intensive and can stall user tasks at times.  To
prevent this, add config DEBUG_KMEMLEAK_AUTO_SCAN to enable/disable auto
scan on boot up.  Also protect first_run with DEBUG_KMEMLEAK_AUTO_SCAN as
this is meant for only first automatic scan.

Link: http://lkml.kernel.org/r/1540231723-7087-1-git-send-email-prpatel@nvidia.comSigned-off-by: NSri Krishna chowdary <schowdary@nvidia.com>
Signed-off-by: NSachin Nikam <snikam@nvidia.com>
Signed-off-by: NPrateek <prpatel@nvidia.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kmemleak_scan() goes through all online nodes and tries to scan all used
pages.

We can do better and use pfn_to_online_page(), so in case we have
CONFIG_MEMORY_HOTPLUG, offlined pages will be skiped automatically.  For
boxes where CONFIG_MEMORY_HOTPLUG is not present, pfn_to_online_page()
will fallback to pfn_valid().

Another little optimization is to check if the page belongs to the node we
are currently checking, so in case we have nodes interleaved we will not
check the same pfn multiple times.

I ran some tests:

Add some memory to node1 and node2 making it interleaved:

(qemu) object_add memory-backend-ram,id=ram0,size=1G
(qemu) device_add pc-dimm,id=dimm0,memdev=ram0,node=1
(qemu) object_add memory-backend-ram,id=ram1,size=1G
(qemu) device_add pc-dimm,id=dimm1,memdev=ram1,node=2
(qemu) object_add memory-backend-ram,id=ram2,size=1G
(qemu) device_add pc-dimm,id=dimm2,memdev=ram2,node=1

Then, we offline that memory:
 # for i in {32..39} ; do echo "offline" > /sys/devices/system/node/node1/memory$i/state;done
 # for i in {48..55} ; do echo "offline" > /sys/devices/system/node/node1/memory$i/state;don
 # for i in {40..47} ; do echo "offline" > /sys/devices/system/node/node2/memory$i/state;done

And we run kmemleak_scan:

 # echo "scan" > /sys/kernel/debug/kmemleak

before the patch:

kmemleak: time spend: 41596 us

after the patch:

kmemleak: time spend: 34899 us

[akpm@linux-foundation.org: remove stray newline, per Oscar]
Link: http://lkml.kernel.org/r/20181206131918.25099-1-osalvador@suse.deSigned-off-by: NOscar Salvador <osalvador@suse.de>
Reviewed-by: NWei Yang <richard.weiyang@gmail.com>
Suggested-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.

The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include <linux/memblock.h>

@@
@@
- #include <linux/bootmem.h>
+ #include <linux/memblock.h>

[sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h]
  Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au
[sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h]
  Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au
[sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
  Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au
Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>