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  1. 12 4月, 2023 12 次提交
    • D
      xfs: don't leak memory when attr fork loading fails · 723ed218
      由 Darrick J. Wong 提交于 
      mainline inclusion
from mainline-v5.19-rc5
commit c78c2d09
category: bugfix
bugzilla: 187164, https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c78c2d0903183a41beb90c56a923e30f90fa91b9

--------------------------------

I observed the following evidence of a memory leak while running xfs/399
from the xfs fsck test suite (edited for brevity):

XFS (sde): Metadata corruption detected at xfs_attr_shortform_verify_struct.part.0+0x7b/0xb0 [xfs], inode 0x1172 attr fork
XFS: Assertion failed: ip->i_af.if_u1.if_data == NULL, file: fs/xfs/libxfs/xfs_inode_fork.c, line: 315
------------[ cut here ]------------
WARNING: CPU: 2 PID: 91635 at fs/xfs/xfs_message.c:104 assfail+0x46/0x4a [xfs]
CPU: 2 PID: 91635 Comm: xfs_scrub Tainted: G        W         5.19.0-rc7-xfsx #rc7 6e6475eb29fd9dda3181f81b7ca7ff961d277a40
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
RIP: 0010:assfail+0x46/0x4a [xfs]
Call Trace:
 <TASK>
 xfs_ifork_zap_attr+0x7c/0xb0
 xfs_iformat_attr_fork+0x86/0x110
 xfs_inode_from_disk+0x41d/0x480
 xfs_iget+0x389/0xd70
 xfs_bulkstat_one_int+0x5b/0x540
 xfs_bulkstat_iwalk+0x1e/0x30
 xfs_iwalk_ag_recs+0xd1/0x160
 xfs_iwalk_run_callbacks+0xb9/0x180
 xfs_iwalk_ag+0x1d8/0x2e0
 xfs_iwalk+0x141/0x220
 xfs_bulkstat+0x105/0x180
 xfs_ioc_bulkstat.constprop.0.isra.0+0xc5/0x130
 xfs_file_ioctl+0xa5f/0xef0
 __x64_sys_ioctl+0x82/0xa0
 do_syscall_64+0x2b/0x80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

This newly-added assertion checks that there aren't any incore data
structures hanging off the incore fork when we're trying to reset its
contents.  From the call trace, it is evident that iget was trying to
construct an incore inode from the ondisk inode, but the attr fork
verifier failed and we were trying to undo all the memory allocations
that we had done earlier.

The three assertions in xfs_ifork_zap_attr check that the caller has
already called xfs_idestroy_fork, which clearly has not been done here.
As the zap function then zeroes the pointers, we've effectively leaked
the memory.

The shortest change would have been to insert an extra call to
xfs_idestroy_fork, but it makes more sense to bundle the _idestroy_fork
call into _zap_attr, since all other callsites call _idestroy_fork
immediately prior to calling _zap_attr.  IOWs, it eliminates one way to
fail.

Note: This change only applies cleanly to 2ed5b09b, since we just
reworked the attr fork lifetime.  However, I think this memory leak has
existed since 0f45a1b2, since the chain xfs_iformat_attr_fork ->
xfs_iformat_local -> xfs_init_local_fork will allocate
ifp->if_u1.if_data, but if xfs_ifork_verify_local_attr fails,
xfs_iformat_attr_fork will free i_afp without freeing any of the stuff
hanging off i_afp.  The solution for older kernels I think is to add the
missing call to xfs_idestroy_fork just prior to calling kmem_cache_free.

Found by fuzzing a.sfattr.hdr.totsize = lastbit in xfs/399.

Fixes: 2ed5b09b ("xfs: make inode attribute forks a permanent part of struct xfs_inode")
Probably-Fixes: 0f45a1b2 ("xfs: improve local fork verification")
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

conflicts:
	fs/xfs/libxfs/xfs_attr_leaf.c
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      723ed218
    • D
      xfs: delete unnecessary NULL checks · 762ff45d
      由 Dan Carpenter 提交于 
      mainline inclusion
from mainline-v5.19-rc5
commit 3f52e016
category: bugfix
bugzilla: 187164, https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3f52e016af600982989b5dee958d313c52483c92

--------------------------------

These NULL check are no long needed after commit 2ed5b09b ("xfs:
make inode attribute forks a permanent part of struct xfs_inode").
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      762ff45d
    • D
      xfs: replace inode fork size macros with functions · ecdd11e4
      由 Darrick J. Wong 提交于 
      mainline inclusion
from mainline-v5.19-rc5
commit c01147d9
category: bugfix
bugzilla: 187164, https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c01147d929899f02a0a8b15e406d12784768ca72

--------------------------------

Replace the shouty macros here with typechecked helper functions.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

conflicts:
	fs/xfs/libxfs/xfs_attr_leaf.c
	fs/xfs/libxfs/xfs_bmap.c
	fs/xfs/libxfs/xfs_bmap_btree.c
	fs/xfs/libxfs/xfs_dir2.c
	fs/xfs/libxfs/xfs_inode_fork.h
	fs/xfs/scrub/symlink.c
	fs/xfs/xfs_itable.c
	fs/xfs/xfs_symlink.c
	fs/xfs/xfs_trace.h
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      ecdd11e4
    • D
      xfs: replace XFS_IFORK_Q with a proper predicate function · ad92c988
      由 Darrick J. Wong 提交于 
      mainline inclusion
from mainline-v5.19-rc5
commit 932b42c6
category: bugfix
bugzilla: 187164, https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=932b42c66cb5d0ca9800b128415b4ad6b1952b3e

--------------------------------

Replace this shouty macro with a real C function that has a more
descriptive name.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

conflicts:
	fs/xfs/libxfs/xfs_attr.h
	fs/xfs/libxfs/xfs_inode_fork.c
	fs/xfs/scrub/btree.c
	fs/xfs/xfs_inode.c
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      ad92c988
    • D
      xfs: use XFS_IFORK_Q to determine the presence of an xattr fork · d79239ec
      由 Darrick J. Wong 提交于 
      mainline inclusion
from mainline-v5.19-rc5
commit e45d7cb2
category: bugfix
bugzilla: 187164, https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e45d7cb2356e6b59fe64da28324025cc6fcd3fbd

--------------------------------

Modify xfs_ifork_ptr to return a NULL pointer if the caller asks for the
attribute fork but i_forkoff is zero.  This eliminates the ambiguity
between i_forkoff and i_af.if_present, which should make it easier to
understand the lifetime of attr forks.

While we're at it, remove the if_present checks around calls to
xfs_idestroy_fork and xfs_ifork_zap_attr since they can both handle attr
forks that have already been torn down.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

conflicts:
	fs/xfs/libxfs/xfs_attr.h
	fs/xfs/libxfs/xfs_inode_fork.c
	fs/xfs/libxfs/xfs_inode_fork.h
	fs/xfs/xfs_icache.c
	fs/xfs/xfs_inode.c
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      d79239ec
    • D
      xfs: make inode attribute forks a permanent part of struct xfs_inode · 947546ab
      由 Darrick J. Wong 提交于 
      mainline inclusion
from mainline-v5.19-rc5
commit 2ed5b09b
category: bugfix
bugzilla: 187164, https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2ed5b09b3e8fc274ae8fecd6ab7c5106a364bed1

--------------------------------

Syzkaller reported a UAF bug a while back:

==================================================================
BUG: KASAN: use-after-free in xfs_ilock_attr_map_shared+0xe3/0xf6 fs/xfs/xfs_inode.c:127
Read of size 4 at addr ffff88802cec919c by task syz-executor262/2958

CPU: 2 PID: 2958 Comm: syz-executor262 Not tainted
5.15.0-0.30.3-20220406_1406 #3
Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7860+a7792d29
04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x82/0xa9 lib/dump_stack.c:106
 print_address_description.constprop.9+0x21/0x2d5 mm/kasan/report.c:256
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold.14+0x7f/0x11b mm/kasan/report.c:459
 xfs_ilock_attr_map_shared+0xe3/0xf6 fs/xfs/xfs_inode.c:127
 xfs_attr_get+0x378/0x4c2 fs/xfs/libxfs/xfs_attr.c:159
 xfs_xattr_get+0xe3/0x150 fs/xfs/xfs_xattr.c:36
 __vfs_getxattr+0xdf/0x13d fs/xattr.c:399
 cap_inode_need_killpriv+0x41/0x5d security/commoncap.c:300
 security_inode_need_killpriv+0x4c/0x97 security/security.c:1408
 dentry_needs_remove_privs.part.28+0x21/0x63 fs/inode.c:1912
 dentry_needs_remove_privs+0x80/0x9e fs/inode.c:1908
 do_truncate+0xc3/0x1e0 fs/open.c:56
 handle_truncate fs/namei.c:3084 [inline]
 do_open fs/namei.c:3432 [inline]
 path_openat+0x30ab/0x396d fs/namei.c:3561
 do_filp_open+0x1c4/0x290 fs/namei.c:3588
 do_sys_openat2+0x60d/0x98c fs/open.c:1212
 do_sys_open+0xcf/0x13c fs/open.c:1228
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0x0
RIP: 0033:0x7f7ef4bb753d
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48
89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73
01 c3 48 8b 0d 1b 79 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007f7ef52c2ed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 0000000000404148 RCX: 00007f7ef4bb753d
RDX: 00007f7ef4bb753d RSI: 0000000000000000 RDI: 0000000020004fc0
RBP: 0000000000404140 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 00007ffd794db37f R14: 00007ffd794db470 R15: 00007f7ef52c2fc0
 </TASK>

Allocated by task 2953:
 kasan_save_stack+0x19/0x38 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x68/0x7c mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook mm/slab.h:519 [inline]
 slab_alloc_node mm/slub.c:3213 [inline]
 slab_alloc mm/slub.c:3221 [inline]
 kmem_cache_alloc+0x11b/0x3eb mm/slub.c:3226
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 xfs_ifork_alloc+0x25/0xa2 fs/xfs/libxfs/xfs_inode_fork.c:287
 xfs_bmap_add_attrfork+0x3f2/0x9b1 fs/xfs/libxfs/xfs_bmap.c:1098
 xfs_attr_set+0xe38/0x12a7 fs/xfs/libxfs/xfs_attr.c:746
 xfs_xattr_set+0xeb/0x1a9 fs/xfs/xfs_xattr.c:59
 __vfs_setxattr+0x11b/0x177 fs/xattr.c:180
 __vfs_setxattr_noperm+0x128/0x5e0 fs/xattr.c:214
 __vfs_setxattr_locked+0x1d4/0x258 fs/xattr.c:275
 vfs_setxattr+0x154/0x33d fs/xattr.c:301
 setxattr+0x216/0x29f fs/xattr.c:575
 __do_sys_fsetxattr fs/xattr.c:632 [inline]
 __se_sys_fsetxattr fs/xattr.c:621 [inline]
 __x64_sys_fsetxattr+0x243/0x2fe fs/xattr.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0x0

Freed by task 2949:
 kasan_save_stack+0x19/0x38 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x21 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xe2/0x10e mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1700 [inline]
 slab_free_freelist_hook mm/slub.c:1726 [inline]
 slab_free mm/slub.c:3492 [inline]
 kmem_cache_free+0xdc/0x3ce mm/slub.c:3508
 xfs_attr_fork_remove+0x8d/0x132 fs/xfs/libxfs/xfs_attr_leaf.c:773
 xfs_attr_sf_removename+0x5dd/0x6cb fs/xfs/libxfs/xfs_attr_leaf.c:822
 xfs_attr_remove_iter+0x68c/0x805 fs/xfs/libxfs/xfs_attr.c:1413
 xfs_attr_remove_args+0xb1/0x10d fs/xfs/libxfs/xfs_attr.c:684
 xfs_attr_set+0xf1e/0x12a7 fs/xfs/libxfs/xfs_attr.c:802
 xfs_xattr_set+0xeb/0x1a9 fs/xfs/xfs_xattr.c:59
 __vfs_removexattr+0x106/0x16a fs/xattr.c:468
 cap_inode_killpriv+0x24/0x47 security/commoncap.c:324
 security_inode_killpriv+0x54/0xa1 security/security.c:1414
 setattr_prepare+0x1a6/0x897 fs/attr.c:146
 xfs_vn_change_ok+0x111/0x15e fs/xfs/xfs_iops.c:682
 xfs_vn_setattr_size+0x5f/0x15a fs/xfs/xfs_iops.c:1065
 xfs_vn_setattr+0x125/0x2ad fs/xfs/xfs_iops.c:1093
 notify_change+0xae5/0x10a1 fs/attr.c:410
 do_truncate+0x134/0x1e0 fs/open.c:64
 handle_truncate fs/namei.c:3084 [inline]
 do_open fs/namei.c:3432 [inline]
 path_openat+0x30ab/0x396d fs/namei.c:3561
 do_filp_open+0x1c4/0x290 fs/namei.c:3588
 do_sys_openat2+0x60d/0x98c fs/open.c:1212
 do_sys_open+0xcf/0x13c fs/open.c:1228
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0x0

The buggy address belongs to the object at ffff88802cec9188
 which belongs to the cache xfs_ifork of size 40
The buggy address is located 20 bytes inside of
 40-byte region [ffff88802cec9188, ffff88802cec91b0)
The buggy address belongs to the page:
page:00000000c3af36a1 refcount:1 mapcount:0 mapping:0000000000000000
index:0x0 pfn:0x2cec9
flags: 0xfffffc0000200(slab|node=0|zone=1|lastcpupid=0x1fffff)
raw: 000fffffc0000200 ffffea00009d2580 0000000600000006 ffff88801a9ffc80
raw: 0000000000000000 0000000080490049 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88802cec9080: fb fb fb fc fc fa fb fb fb fb fc fc fb fb fb fb
 ffff88802cec9100: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc
>ffff88802cec9180: fc fa fb fb fb fb fc fc fa fb fb fb fb fc fc fb
                            ^
 ffff88802cec9200: fb fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb
 ffff88802cec9280: fb fb fc fc fa fb fb fb fb fc fc fa fb fb fb fb
==================================================================

The root cause of this bug is the unlocked access to xfs_inode.i_afp
from the getxattr code paths while trying to determine which ILOCK mode
to use to stabilize the xattr data.  Unfortunately, the VFS does not
acquire i_rwsem when vfs_getxattr (or listxattr) call into the
filesystem, which means that getxattr can race with a removexattr that's
tearing down the attr fork and crash:

xfs_attr_set:                          xfs_attr_get:
xfs_attr_fork_remove:                  xfs_ilock_attr_map_shared:

xfs_idestroy_fork(ip->i_afp);
kmem_cache_free(xfs_ifork_cache, ip->i_afp);

                                       if (ip->i_afp &&

ip->i_afp = NULL;

                                           xfs_need_iread_extents(ip->i_afp))
                                       <KABOOM>

ip->i_forkoff = 0;

Regrettably, the VFS is much more lax about i_rwsem and getxattr than
is immediately obvious -- not only does it not guarantee that we hold
i_rwsem, it actually doesn't guarantee that we *don't* hold it either.
The getxattr system call won't acquire the lock before calling XFS, but
the file capabilities code calls getxattr with and without i_rwsem held
to determine if the "security.capabilities" xattr is set on the file.

Fixing the VFS locking requires a treewide investigation into every code
path that could touch an xattr and what i_rwsem state it expects or sets
up.  That could take years or even prove impossible; fortunately, we
can fix this UAF problem inside XFS.

An earlier version of this patch used smp_wmb in xfs_attr_fork_remove to
ensure that i_forkoff is always zeroed before i_afp is set to null and
changed the read paths to use smp_rmb before accessing i_forkoff and
i_afp, which avoided these UAF problems.  However, the patch author was
too busy dealing with other problems in the meantime, and by the time he
came back to this issue, the situation had changed a bit.

On a modern system with selinux, each inode will always have at least
one xattr for the selinux label, so it doesn't make much sense to keep
incurring the extra pointer dereference.  Furthermore, Allison's
upcoming parent pointer patchset will also cause nearly every inode in
the filesystem to have extended attributes.  Therefore, make the inode
attribute fork structure part of struct xfs_inode, at a cost of 40 more
bytes.

This patch adds a clunky if_present field where necessary to maintain
the existing logic of xattr fork null pointer testing in the existing
codebase.  The next patch switches the logic over to XFS_IFORK_Q and it
all goes away.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

conflicts:
	fs/xfs/libxfs/xfs_attr.c
	fs/xfs/libxfs/xfs_attr.h
	fs/xfs/libxfs/xfs_attr_leaf.c
	fs/xfs/libxfs/xfs_bmap.c
	fs/xfs/libxfs/xfs_inode_buf.c
	fs/xfs/libxfs/xfs_inode_fork.c
	fs/xfs/libxfs/xfs_inode_fork.h
	fs/xfs/xfs_attr_inactive.c
	fs/xfs/xfs_attr_list.c
	fs/xfs/xfs_icache.c
	fs/xfs/xfs_inode.c
	fs/xfs/xfs_inode.h
	fs/xfs/xfs_inode_item.c
	fs/xfs/xfs_itable.c
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      947546ab
    • D
      xfs: convert XFS_IFORK_PTR to a static inline helper · 34ba4153
      由 Darrick J. Wong 提交于 
      mainline inclusion
from mainline-v5.19-rc5
commit 732436ef
category: bugfix
bugzilla: 187164, https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=732436ef916b4f338d672ea56accfdb11e8d0732

--------------------------------

We're about to make this logic do a bit more, so convert the macro to a
static inline function for better typechecking and fewer shouty macros.
No functional changes here.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

conflicts:
	fs/xfs/libxfs/xfs_bmap.c
	fs/xfs/libxfs/xfs_bmap_btree.c
	fs/xfs/libxfs/xfs_inode_fork.c
	fs/xfs/libxfs/xfs_inode_fork.h
	fs/xfs/scrub/bmap.c
	fs/xfs/scrub/symlink.c
	fs/xfs/xfs_inode.c
	fs/xfs/xfs_ioctl.c
	fs/xfs/xfs_qm.c
	fs/xfs/xfs_reflink.c
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      34ba4153
    • B
      xfs: don't reuse busy extents on extent trim · 63c2dc44
      由 Brian Foster 提交于 
      mainline inclusion
from mainline-v5.11-rc4
commit 06058bc4
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=06058bc40534530e617e5623775c53bb24f032cb

--------------------------------

Freed extents are marked busy from the point the freeing transaction
commits until the associated CIL context is checkpointed to the log.
This prevents reuse and overwrite of recently freed blocks before
the changes are committed to disk, which can lead to corruption
after a crash. The exception to this rule is that metadata
allocation is allowed to reuse busy extents because metadata changes
are also logged.

As of commit 97d3ac75 ("xfs: exact busy extent tracking"), XFS
has allowed modification or complete invalidation of outstanding
busy extents for metadata allocations. This implementation assumes
that use of the associated extent is imminent, which is not always
the case. For example, the trimmed extent might not satisfy the
minimum length of the allocation request, or the allocation
algorithm might be involved in a search for the optimal result based
on locality.

generic/019 reproduces a corruption caused by this scenario. First,
a metadata block (usually a bmbt or symlink block) is freed from an
inode. A subsequent bmbt split on an unrelated inode attempts a near
mode allocation request that invalidates the busy block during the
search, but does not ultimately allocate it. Due to the busy state
invalidation, the block is no longer considered busy to subsequent
allocation. A direct I/O write request immediately allocates the
block and writes to it. Finally, the filesystem crashes while in a
state where the initial metadata block free had not committed to the
on-disk log. After recovery, the original metadata block is in its
original location as expected, but has been corrupted by the
aforementioned dio.

This demonstrates that it is fundamentally unsafe to modify busy
extent state for extents that are not guaranteed to be allocated.
This applies to pretty much all of the code paths that currently
trim busy extents for one reason or another. Therefore to address
this problem, drop the reuse mechanism from the busy extent trim
path. This code already knows how to return partial non-busy ranges
of the targeted free extent and higher level code tracks the busy
state of the allocation attempt. If a block allocation fails where
one or more candidate extents is busy, we force the log and retry
the allocation.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NChandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NYang Erkun <yangerkun@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      63c2dc44
    • Z
      fs/xfs: convert comma to semicolon · b53af989
      由 Zheng Yongjun 提交于 
      mainline inclusion
from mainline-v5.10-rc5
commit 1189686e
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1189686e5440041057f8cc21a7c1d13bb6642cb9

--------------------------------

Replace a comma between expression statements by a semicolon.
Signed-off-by: NZheng Yongjun <zhengyongjun3@huawei.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NYang Erkun <yangerkun@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      b53af989
    • D
      xfs: xfs_ail_push_all_sync() stalls when racing with updates · 6d1cae97
      由 Dave Chinner 提交于 
      mainline inclusion
from mainline-v5.17-rc6
commit 941fbdfd
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=941fbdfd6dd0f1d7961c28123b5460912f678cb5

--------------------------------

xfs_ail_push_all_sync() has a loop like this:

while max_ail_lsn {
	prepare_to_wait(ail_empty)
	target = max_ail_lsn
	wake_up(ail_task);
	schedule()
}

Which is designed to sleep until the AIL is emptied. When
xfs_ail_update_finish() moves the tail of the log, it does:

	if (list_empty(&ailp->ail_head))
		wake_up_all(&ailp->ail_empty);

So it will only wake up the sync push waiter when the AIL goes
empty. If, by the time the push waiter has woken, the AIL has more
in it, it will reset the target, wake the push task and go back to
sleep.

The problem here is that if the AIL is having items added to it
when xfs_ail_push_all_sync() is called, then they may get inserted
into the AIL at a LSN higher than the target LSN. At this point,
xfsaild_push() will see that the target is X, the item LSNs are
(X+N) and skip over them, hence never pushing the out.

The result of this the AIL will not get emptied by the AIL push
thread, hence xfs_ail_finish_update() will never see the AIL being
empty even if it moves the tail. Hence xfs_ail_push_all_sync() never
gets woken and hence cannot update the push target to capture the
items beyond the current target on the LSN.

This is a TOCTOU type of issue so the way to avoid it is to not
use the push target at all for sync pushes. We know that a sync push
is being requested by the fact the ail_empty wait queue is active,
hence the xfsaild can just set the target to max_ail_lsn on every
push that we see the wait queue active. Hence we no longer will
leave items on the AIL that are beyond the LSN sampled at the start
of a sync push.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChandan Babu R <chandan.babu@oracle.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NYang Erkun <yangerkun@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      6d1cae97
    • D
      xfs: check buffer pin state after locking in delwri_submit · 9781b974
      由 Dave Chinner 提交于 
      mainline inclusion
from mainline-v5.17-rc6
commit dbd0f529
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dbd0f5299302f8506637592e2373891a748c6990

--------------------------------

AIL flushing can get stuck here:

[316649.005769] INFO: task xfsaild/pmem1:324525 blocked for more than 123 seconds.
[316649.007807]       Not tainted 5.17.0-rc6-dgc+ #975
[316649.009186] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[316649.011720] task:xfsaild/pmem1   state:D stack:14544 pid:324525 ppid:     2 flags:0x00004000
[316649.014112] Call Trace:
[316649.014841]  <TASK>
[316649.015492]  __schedule+0x30d/0x9e0
[316649.017745]  schedule+0x55/0xd0
[316649.018681]  io_schedule+0x4b/0x80
[316649.019683]  xfs_buf_wait_unpin+0x9e/0xf0
[316649.021850]  __xfs_buf_submit+0x14a/0x230
[316649.023033]  xfs_buf_delwri_submit_buffers+0x107/0x280
[316649.024511]  xfs_buf_delwri_submit_nowait+0x10/0x20
[316649.025931]  xfsaild+0x27e/0x9d0
[316649.028283]  kthread+0xf6/0x120
[316649.030602]  ret_from_fork+0x1f/0x30

in the situation where flushing gets preempted between the unpin
check and the buffer trylock under nowait conditions:

	blk_start_plug(&plug);
	list_for_each_entry_safe(bp, n, buffer_list, b_list) {
		if (!wait_list) {
			if (xfs_buf_ispinned(bp)) {
				pinned++;
				continue;
			}
Here >>>>>>
			if (!xfs_buf_trylock(bp))
				continue;

This means submission is stuck until something else triggers a log
force to unpin the buffer.

To get onto the delwri list to begin with, the buffer pin state has
already been checked, and hence it's relatively rare we get a race
between flushing and encountering a pinned buffer in delwri
submission to begin with. Further, to increase the pin count the
buffer has to be locked, so the only way we can hit this race
without failing the trylock is to be preempted between the pincount
check seeing zero and the trylock being run.

Hence to avoid this problem, just invert the order of trylock vs
pin check. We shouldn't hit that many pinned buffers here, so
optimising away the trylock for pinned buffers should not matter for
performance at all.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChandan Babu R <chandan.babu@oracle.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NYang Erkun <yangerkun@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      9781b974
    • D
      xfs: log worker needs to start before intent/unlink recovery · 74d73186
      由 Dave Chinner 提交于 
      mainline inclusion
from mainline-v5.17-rc6
commit a9a4bc8c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a9a4bc8c76d747aa40b30e2dfc176c781f353a08

--------------------------------

After 963 iterations of generic/530, it deadlocked during recovery
on a pinned inode cluster buffer like so:

XFS (pmem1): Starting recovery (logdev: internal)
INFO: task kworker/8:0:306037 blocked for more than 122 seconds.
      Not tainted 5.17.0-rc6-dgc+ #975
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/8:0     state:D stack:13024 pid:306037 ppid:     2 flags:0x00004000
Workqueue: xfs-inodegc/pmem1 xfs_inodegc_worker
Call Trace:
 <TASK>
 __schedule+0x30d/0x9e0
 schedule+0x55/0xd0
 schedule_timeout+0x114/0x160
 __down+0x99/0xf0
 down+0x5e/0x70
 xfs_buf_lock+0x36/0xf0
 xfs_buf_find+0x418/0x850
 xfs_buf_get_map+0x47/0x380
 xfs_buf_read_map+0x54/0x240
 xfs_trans_read_buf_map+0x1bd/0x490
 xfs_imap_to_bp+0x4f/0x70
 xfs_iunlink_map_ino+0x66/0xd0
 xfs_iunlink_map_prev.constprop.0+0x148/0x2f0
 xfs_iunlink_remove_inode+0xf2/0x1d0
 xfs_inactive_ifree+0x1a3/0x900
 xfs_inode_unlink+0xcc/0x210
 xfs_inodegc_worker+0x1ac/0x2f0
 process_one_work+0x1ac/0x390
 worker_thread+0x56/0x3c0
 kthread+0xf6/0x120
 ret_from_fork+0x1f/0x30
 </TASK>
task:mount           state:D stack:13248 pid:324509 ppid:324233 flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x30d/0x9e0
 schedule+0x55/0xd0
 schedule_timeout+0x114/0x160
 __down+0x99/0xf0
 down+0x5e/0x70
 xfs_buf_lock+0x36/0xf0
 xfs_buf_find+0x418/0x850
 xfs_buf_get_map+0x47/0x380
 xfs_buf_read_map+0x54/0x240
 xfs_trans_read_buf_map+0x1bd/0x490
 xfs_imap_to_bp+0x4f/0x70
 xfs_iget+0x300/0xb40
 xlog_recover_process_one_iunlink+0x4c/0x170
 xlog_recover_process_iunlinks.isra.0+0xee/0x130
 xlog_recover_finish+0x57/0x110
 xfs_log_mount_finish+0xfc/0x1e0
 xfs_mountfs+0x540/0x910
 xfs_fs_fill_super+0x495/0x850
 get_tree_bdev+0x171/0x270
 xfs_fs_get_tree+0x15/0x20
 vfs_get_tree+0x24/0xc0
 path_mount+0x304/0xba0
 __x64_sys_mount+0x108/0x140
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
 </TASK>
task:xfsaild/pmem1   state:D stack:14544 pid:324525 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x30d/0x9e0
 schedule+0x55/0xd0
 io_schedule+0x4b/0x80
 xfs_buf_wait_unpin+0x9e/0xf0
 __xfs_buf_submit+0x14a/0x230
 xfs_buf_delwri_submit_buffers+0x107/0x280
 xfs_buf_delwri_submit_nowait+0x10/0x20
 xfsaild+0x27e/0x9d0
 kthread+0xf6/0x120
 ret_from_fork+0x1f/0x30

We have the mount process waiting on an inode cluster buffer read,
inodegc doing unlink waiting on the same inode cluster buffer, and
the AIL push thread blocked in writeback waiting for the inode
cluster buffer to become unpinned.

What has happened here is that the AIL push thread has raced with
the inodegc process modifying, committing and pinning the inode
cluster buffer here in xfs_buf_delwri_submit_buffers() here:

	blk_start_plug(&plug);
	list_for_each_entry_safe(bp, n, buffer_list, b_list) {
		if (!wait_list) {
			if (xfs_buf_ispinned(bp)) {
				pinned++;
				continue;
			}
Here >>>>>>
			if (!xfs_buf_trylock(bp))
				continue;

Basically, the AIL has found the buffer wasn't pinned and got the
lock without blocking, but then the buffer was pinned. This implies
the processing here was pre-empted between the pin check and the
lock, because the pin count can only be increased while holding the
buffer locked. Hence when it has gone to submit the IO, it has
blocked waiting for the buffer to be unpinned.

With all executing threads now waiting on the buffer to be unpinned,
we normally get out of situations like this via the background log
worker issuing a log force which will unpinned stuck buffers like
this. But at this point in recovery, we haven't started the log
worker. In fact, the first thing we do after processing intents and
unlinked inodes is *start the log worker*. IOWs, we start it too
late to have it break deadlocks like this.

Avoid this and any other similar deadlock vectors in intent and
unlinked inode recovery by starting the log worker before we recover
intents and unlinked inodes. This part of recovery runs as though
the filesystem is fully active, so we really should have the same
infrastructure running as we normally do at runtime.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NChandan Babu R <chandan.babu@oracle.com>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NLong Li <leo.lilong@huawei.com>
Reviewed-by: NYang Erkun <yangerkun@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
      74d73186
  3. 04 4月, 2023 19 次提交
  5. 03 4月, 2023 3 次提交
  7. 01 4月, 2023 1 次提交
  9. 31 3月, 2023 1 次提交
  11. 29 3月, 2023 4 次提交