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  1. 14 3月, 2018 3 次提交
  3. 13 3月, 2018 2 次提交
  5. 09 3月, 2018 4 次提交
  7. 01 3月, 2018 4 次提交
  9. 27 2月, 2018 3 次提交
    • J
      genhd: Fix BUG in blkdev_open() · 56c0908c
      由 Jan Kara 提交于 
      When two blkdev_open() calls for a partition race with device removal
and recreation, we can hit BUG_ON(!bd_may_claim(bdev, whole, holder)) in
blkdev_open(). The race can happen as follows:

CPU0				CPU1			CPU2
							del_gendisk()
							  bdev_unhash_inode(part1);

blkdev_open(part1, O_EXCL)	blkdev_open(part1, O_EXCL)
  bdev = bd_acquire()		  bdev = bd_acquire()
  blkdev_get(bdev)
    bd_start_claiming(bdev)
      - finds old inode 'whole'
      bd_prepare_to_claim() -> 0
							  bdev_unhash_inode(whole);
							<device removed>
							<new device under same
							 number created>
				  blkdev_get(bdev);
				    bd_start_claiming(bdev)
				      - finds new inode 'whole'
				      bd_prepare_to_claim()
					- this also succeeds as we have
					  different 'whole' here...
					- bad things happen now as we
					  have two exclusive openers of
					  the same bdev

The problem here is that block device opens can see various intermediate
states while gendisk is shutting down and then being recreated.

We fix the problem by introducing new lookup_sem in gendisk that
synchronizes gendisk deletion with get_gendisk() and furthermore by
making sure that get_gendisk() does not return gendisk that is being (or
has been) deleted. This makes sure that once we ever manage to look up
newly created bdev inode, we are also guaranteed that following
get_gendisk() will either return failure (and we fail open) or it
returns gendisk for the new device and following bdget_disk() will
return new bdev inode (i.e., blkdev_open() follows the path as if it is
completely run after new device is created).
Reported-and-analyzed-by: NHou Tao <houtao1@huawei.com>
Tested-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      56c0908c
    • J
      genhd: Add helper put_disk_and_module() · 9df6c299
      由 Jan Kara 提交于 
      Add a proper counterpart to get_disk_and_module() -
put_disk_and_module(). Currently it is opencoded in several places.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      9df6c299
    • J
      genhd: Rename get_disk() to get_disk_and_module() · 3079c22e
      由 Jan Kara 提交于 
      Rename get_disk() to get_disk_and_module() to make sure what the
function does. It's not a great name but at least it is now clear that
put_disk() is not it's counterpart.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      3079c22e
  11. 23 2月, 2018 2 次提交
  13. 22 2月, 2018 5 次提交
    • A
      bug.h: work around GCC PR82365 in BUG() · 173a3efd
      由 Arnd Bergmann 提交于 
      Looking at functions with large stack frames across all architectures
led me discovering that BUG() suffers from the same problem as
fortify_panic(), which I've added a workaround for already.

In short, variables that go out of scope by calling a noreturn function
or __builtin_unreachable() keep using stack space in functions
afterwards.

A workaround that was identified is to insert an empty assembler
statement just before calling the function that doesn't return.  I'm
adding a macro "barrier_before_unreachable()" to document this, and
insert calls to that in all instances of BUG() that currently suffer
from this problem.

The files that saw the largest change from this had these frame sizes
before, and much less with my patch:

  fs/ext4/inode.c:82:1: warning: the frame size of 1672 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/namei.c:434:1: warning: the frame size of 904 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/super.c:2279:1: warning: the frame size of 1160 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/xattr.c:146:1: warning: the frame size of 1168 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/f2fs/inode.c:152:1: warning: the frame size of 1424 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_core.c:1195:1: warning: the frame size of 1068 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_core.c:395:1: warning: the frame size of 1084 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_ftp.c:298:1: warning: the frame size of 928 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_ftp.c:418:1: warning: the frame size of 908 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_lblcr.c:718:1: warning: the frame size of 960 bytes is larger than 800 bytes [-Wframe-larger-than=]
  drivers/net/xen-netback/netback.c:1500:1: warning: the frame size of 1088 bytes is larger than 800 bytes [-Wframe-larger-than=]

In case of ARC and CRIS, it turns out that the BUG() implementation
actually does return (or at least the compiler thinks it does),
resulting in lots of warnings about uninitialized variable use and
leaving noreturn functions, such as:

  block/cfq-iosched.c: In function 'cfq_async_queue_prio':
  block/cfq-iosched.c:3804:1: error: control reaches end of non-void function [-Werror=return-type]
  include/linux/dmaengine.h: In function 'dma_maxpq':
  include/linux/dmaengine.h:1123:1: error: control reaches end of non-void function [-Werror=return-type]

This makes them call __builtin_trap() instead, which should normally
dump the stack and kill the current process, like some of the other
architectures already do.

I tried adding barrier_before_unreachable() to panic() and
fortify_panic() as well, but that had very little effect, so I'm not
submitting that patch.

Vineet said:

: For ARC, it is double win.
:
: 1. Fixes 3 -Wreturn-type warnings
:
: | ../net/core/ethtool.c:311:1: warning: control reaches end of non-void function
: [-Wreturn-type]
: | ../kernel/sched/core.c:3246:1: warning: control reaches end of non-void function
: [-Wreturn-type]
: | ../include/linux/sunrpc/svc_xprt.h:180:1: warning: control reaches end of
: non-void function [-Wreturn-type]
:
: 2.  bloat-o-meter reports code size improvements as gcc elides the
:    generated code for stack return.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
Link: http://lkml.kernel.org/r/20171219114112.939391-1-arnd@arndb.deSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: Vineet Gupta <vgupta@synopsys.com>	[arch/arc]
Tested-by: Vineet Gupta <vgupta@synopsys.com>	[arch/arc]
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Christopher Li <sparse@chrisli.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      173a3efd
    • S
      mm, mlock, vmscan: no more skipping pagevecs · 9c4e6b1a
      由 Shakeel Butt 提交于 
      When a thread mlocks an address space backed either by file pages which
are currently not present in memory or swapped out anon pages (not in
swapcache), a new page is allocated and added to the local pagevec
(lru_add_pvec), I/O is triggered and the thread then sleeps on the page.
On I/O completion, the thread can wake on a different CPU, the mlock
syscall will then sets the PageMlocked() bit of the page but will not be
able to put that page in unevictable LRU as the page is on the pagevec
of a different CPU.  Even on drain, that page will go to evictable LRU
because the PageMlocked() bit is not checked on pagevec drain.

The page will eventually go to right LRU on reclaim but the LRU stats
will remain skewed for a long time.

This patch puts all the pages, even unevictable, to the pagevecs and on
the drain, the pages will be added on their LRUs correctly by checking
their evictability.  This resolves the mlocked pages on pagevec of other
CPUs issue because when those pagevecs will be drained, the mlocked file
pages will go to unevictable LRU.  Also this makes the race with munlock
easier to resolve because the pagevec drains happen in LRU lock.

However there is still one place which makes a page evictable and does
PageLRU check on that page without LRU lock and needs special attention.
TestClearPageMlocked() and isolate_lru_page() in clear_page_mlock().

	#0: __pagevec_lru_add_fn	#1: clear_page_mlock

	SetPageLRU()			if (!TestClearPageMlocked())
					  return
	smp_mb() // <--required
					// inside does PageLRU
	if (!PageMlocked())		if (isolate_lru_page())
	  move to evictable LRU		  putback_lru_page()
	else
	  move to unevictable LRU

In '#1', TestClearPageMlocked() provides full memory barrier semantics
and thus the PageLRU check (inside isolate_lru_page) can not be
reordered before it.

In '#0', without explicit memory barrier, the PageMlocked() check can be
reordered before SetPageLRU().  If that happens, '#0' can put a page in
unevictable LRU and '#1' might have just cleared the Mlocked bit of that
page but fails to isolate as PageLRU fails as '#0' still hasn't set
PageLRU bit of that page.  That page will be stranded on the unevictable
LRU.

There is one (good) side effect though.  Without this patch, the pages
allocated for System V shared memory segment are added to evictable LRUs
even after shmctl(SHM_LOCK) on that segment.  This patch will correctly
put such pages to unevictable LRU.

Link: http://lkml.kernel.org/r/20171121211241.18877-1-shakeelb@google.comSigned-off-by: NShakeel Butt <shakeelb@google.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shaohua Li <shli@fb.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9c4e6b1a
    • J
      mm: memcontrol: fix NR_WRITEBACK leak in memcg and system stats · c3cc3911
      由 Johannes Weiner 提交于 
      After commit a983b5eb ("mm: memcontrol: fix excessive complexity in
memory.stat reporting"), we observed slowly upward creeping NR_WRITEBACK
counts over the course of several days, both the per-memcg stats as well
as the system counter in e.g.  /proc/meminfo.

The conversion from full per-cpu stat counts to per-cpu cached atomic
stat counts introduced an irq-unsafe RMW operation into the updates.

Most stat updates come from process context, but one notable exception
is the NR_WRITEBACK counter.  While writebacks are issued from process
context, they are retired from (soft)irq context.

When writeback completions interrupt the RMW counter updates of new
writebacks being issued, the decs from the completions are lost.

Since the global updates are routed through the joint lruvec API, both
the memcg counters as well as the system counters are affected.

This patch makes the joint stat and event API irq safe.

Link: http://lkml.kernel.org/r/20180203082353.17284-1-hannes@cmpxchg.org
Fixes: a983b5eb ("mm: memcontrol: fix excessive complexity in memory.stat reporting")
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Debugged-by: NTejun Heo <tj@kernel.org>
Reviewed-by: NRik van Riel <riel@surriel.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c3cc3911
    • A
      Kbuild: always define endianess in kconfig.h · 101110f6
      由 Arnd Bergmann 提交于 
      Build testing with LTO found a couple of files that get compiled
differently depending on whether asm/byteorder.h gets included early
enough or not.  In particular, include/asm-generic/qrwlock_types.h is
affected by this, but there are probably others as well.

The symptom is a series of LTO link time warnings, including these:

    net/netlabel/netlabel_unlabeled.h:223: error: type of 'netlbl_unlhsh_add' does not match original declaration [-Werror=lto-type-mismatch]
     int netlbl_unlhsh_add(struct net *net,
    net/netlabel/netlabel_unlabeled.c:377: note: 'netlbl_unlhsh_add' was previously declared here

    include/net/ipv6.h:360: error: type of 'ipv6_renew_options_kern' does not match original declaration [-Werror=lto-type-mismatch]
     ipv6_renew_options_kern(struct sock *sk,
    net/ipv6/exthdrs.c:1162: note: 'ipv6_renew_options_kern' was previously declared here

    net/core/dev.c:761: note: 'dev_get_by_name_rcu' was previously declared here
     struct net_device *dev_get_by_name_rcu(struct net *net, const char *name)
    net/core/dev.c:761: note: code may be misoptimized unless -fno-strict-aliasing is used

    drivers/gpu/drm/i915/i915_drv.h:3377: error: type of 'i915_gem_object_set_to_wc_domain' does not match original declaration [-Werror=lto-type-mismatch]
     i915_gem_object_set_to_wc_domain(struct drm_i915_gem_object *obj, bool write);
    drivers/gpu/drm/i915/i915_gem.c:3639: note: 'i915_gem_object_set_to_wc_domain' was previously declared here

    include/linux/debugfs.h:92:9: error: type of 'debugfs_attr_read' does not match original declaration [-Werror=lto-type-mismatch]
     ssize_t debugfs_attr_read(struct file *file, char __user *buf,
    fs/debugfs/file.c:318: note: 'debugfs_attr_read' was previously declared here

    include/linux/rwlock_api_smp.h:30: error: type of '_raw_read_unlock' does not match original declaration [-Werror=lto-type-mismatch]
     void __lockfunc _raw_read_unlock(rwlock_t *lock) __releases(lock);
    kernel/locking/spinlock.c:246:26: note: '_raw_read_unlock' was previously declared here

    include/linux/fs.h:3308:5: error: type of 'simple_attr_open' does not match original declaration [-Werror=lto-type-mismatch]
     int simple_attr_open(struct inode *inode, struct file *file,
    fs/libfs.c:795: note: 'simple_attr_open' was previously declared here

All of the above are caused by include/asm-generic/qrwlock_types.h
failing to include asm/byteorder.h after commit e0d02285
("locking/qrwlock: Use 'struct qrwlock' instead of 'struct __qrwlock'")
in linux-4.15.

Similar bugs may or may not exist in older kernels as well, but there is
no easy way to test those with link-time optimizations, and kernels
before 4.14 are harder to fix because they don't have Babu's patch
series

We had similar issues with CONFIG_ symbols in the past and ended up
always including the configuration headers though linux/kconfig.h.  This
works around the issue through that same file, defining either
__BIG_ENDIAN or __LITTLE_ENDIAN depending on CONFIG_CPU_BIG_ENDIAN,
which is now always set on all architectures since commit 4c97a0c8
("arch: define CPU_BIG_ENDIAN for all fixed big endian archs").

Link: http://lkml.kernel.org/r/20180202154104.1522809-2-arnd@arndb.deSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Babu Moger <babu.moger@amd.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@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>
      101110f6
    • A
      include/linux/sched/mm.h: re-inline mmdrop() · d34bc48f
      由 Andrew Morton 提交于 
      As Peter points out, Doing a CALL+RET for just the decrement is a bit silly.

Fixes: d70f2a14 ("include/linux/sched/mm.h: uninline mmdrop_async(), etc")
Acked-by: NPeter Zijlstra (Intel) <peterz@infraded.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d34bc48f
  15. 17 2月, 2018 1 次提交
  17. 16 2月, 2018 1 次提交
  19. 15 2月, 2018 2 次提交
  21. 13 2月, 2018 3 次提交
    • T
      x86/mm, mm/hwpoison: Don't unconditionally unmap kernel 1:1 pages · fd0e786d
      由 Tony Luck 提交于 
      In the following commit:

  ce0fa3e5 ("x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages")

... we added code to memory_failure() to unmap the page from the
kernel 1:1 virtual address space to avoid speculative access to the
page logging additional errors.

But memory_failure() may not always succeed in taking the page offline,
especially if the page belongs to the kernel.  This can happen if
there are too many corrected errors on a page and either mcelog(8)
or drivers/ras/cec.c asks to take a page offline.

Since we remove the 1:1 mapping early in memory_failure(), we can
end up with the page unmapped, but still in use. On the next access
the kernel crashes :-(

There are also various debug paths that call memory_failure() to simulate
occurrence of an error. Since there is no actual error in memory, we
don't need to map out the page for those cases.

Revert most of the previous attempt and keep the solution local to
arch/x86/kernel/cpu/mcheck/mce.c. Unmap the page only when:

	1) there is a real error
	2) memory_failure() succeeds.

All of this only applies to 64-bit systems. 32-bit kernel doesn't map
all of memory into kernel space. It isn't worth adding the code to unmap
the piece that is mapped because nobody would run a 32-bit kernel on a
machine that has recoverable machine checks.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert (Persistent Memory) <elliott@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org #v4.14
Fixes: ce0fa3e5 ("x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages")
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      fd0e786d
    • T
      locking/semaphore: Update the file path in documentation · 2dd6fd2e
      由 Tycho Andersen 提交于 
      While reading this header I noticed that the locking stuff has moved to
kernel/locking/*, so update the path in semaphore.h to point to that.
Signed-off-by: NTycho Andersen <tycho@tycho.ws>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180201114119.1090-1-tycho@tycho.wsSigned-off-by: NIngo Molnar <mingo@kernel.org>
      2dd6fd2e
    • jia zhang's avatar
      vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page · 595dd46e
      由 jia zhang 提交于 
      Commit:

  df04abfd ("fs/proc/kcore.c: Add bounce buffer for ktext data")

... introduced a bounce buffer to work around CONFIG_HARDENED_USERCOPY=y.
However, accessing the vsyscall user page will cause an SMAP fault.

Replace memcpy() with copy_from_user() to fix this bug works, but adding
a common way to handle this sort of user page may be useful for future.

Currently, only vsyscall page requires KCORE_USER.
Signed-off-by: jia zhang's avatarJia Zhang <zhang.jia@linux.alibaba.com>
Reviewed-by: NJiri Olsa <jolsa@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1518446694-21124-2-git-send-email-zhang.jia@linux.alibaba.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      595dd46e
  23. 12 2月, 2018 7 次提交
  25. 10 2月, 2018 2 次提交
  27. 09 2月, 2018 1 次提交
    • M
      net: Extra '_get' in declaration of arch_get_platform_mac_address · e728789c
      由 Mathieu Malaterre 提交于 
      In commit c7f5d105 ("net: Add eth_platform_get_mac_address() helper."),
two declarations were added:

  int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr);
  unsigned char *arch_get_platform_get_mac_address(void);

An extra '_get' was introduced in arch_get_platform_get_mac_address, remove
it. Fix compile warning using W=1:

  CC      net/ethernet/eth.o
net/ethernet/eth.c:523:24: warning: no previous prototype for ‘arch_get_platform_mac_address’ [-Wmissing-prototypes]
 unsigned char * __weak arch_get_platform_mac_address(void)
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  AR      net/ethernet/built-in.o
Signed-off-by: NMathieu Malaterre <malat@debian.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e728789c