| Message ID | 20210907055659.3182992-1-naohiro.aota@wdc.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/kmemleak: allow __GFP_NOLOCKDEP passed to kmemleak's gfp | expand |
On Tue, Sep 07, 2021 at 02:56:59PM +0900, Naohiro Aota wrote: > 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 6dcde60efd94 ("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 Acked-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 73d46d16d575..1f4868cbba22 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -113,7 +113,8 @@ #define BYTES_PER_POINTER sizeof(void *) /* GFP bitmask for kmemleak internal allocations */ -#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \ +#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC | \ + __GFP_NOLOCKDEP)) | \ __GFP_NORETRY | __GFP_NOMEMALLOC | \ __GFP_NOWARN)
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 6dcde60efd94 ("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 Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> --- mm/kmemleak.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)