4.19-stable review patch. If anyone has any objections, please let me know.
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From: Andrey Ryabinin ryabinin.a.a@gmail.com
commit 6fe60465e1d53ea321ee909be26d97529e8f746c upstream.
If stack_depot_save_flags() allocates memory it always drops __GFP_NOLOCKDEP flag. So when KASAN tries to track __GFP_NOLOCKDEP allocation we may end up with lockdep splat like bellow:
====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc3+ #49 Not tainted ------------------------------------------------------ kswapd0/149 is trying to acquire lock: ffff88811346a920 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_reclaim_inode+0x3ac/0x590 [xfs]
but task is already holding lock: ffffffff8bb33100 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x5d9/0xad0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: __lock_acquire+0x7da/0x1030 lock_acquire+0x15d/0x400 fs_reclaim_acquire+0xb5/0x100 prepare_alloc_pages.constprop.0+0xc5/0x230 __alloc_pages+0x12a/0x3f0 alloc_pages_mpol+0x175/0x340 stack_depot_save_flags+0x4c5/0x510 kasan_save_stack+0x30/0x40 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x83/0x90 kmem_cache_alloc+0x15e/0x4a0 __alloc_object+0x35/0x370 __create_object+0x22/0x90 __kmalloc_node_track_caller+0x477/0x5b0 krealloc+0x5f/0x110 xfs_iext_insert_raw+0x4b2/0x6e0 [xfs] xfs_iext_insert+0x2e/0x130 [xfs] xfs_iread_bmbt_block+0x1a9/0x4d0 [xfs] xfs_btree_visit_block+0xfb/0x290 [xfs] xfs_btree_visit_blocks+0x215/0x2c0 [xfs] xfs_iread_extents+0x1a2/0x2e0 [xfs] xfs_buffered_write_iomap_begin+0x376/0x10a0 [xfs] iomap_iter+0x1d1/0x2d0 iomap_file_buffered_write+0x120/0x1a0 xfs_file_buffered_write+0x128/0x4b0 [xfs] vfs_write+0x675/0x890 ksys_write+0xc3/0x160 do_syscall_64+0x94/0x170 entry_SYSCALL_64_after_hwframe+0x71/0x79
Always preserve __GFP_NOLOCKDEP to fix this.
Link: https://lkml.kernel.org/r/20240418141133.22950-1-ryabinin.a.a@gmail.com Fixes: cd11016e5f52 ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB") Signed-off-by: Andrey Ryabinin ryabinin.a.a@gmail.com Reported-by: Xiubo Li xiubli@redhat.com Closes: https://lore.kernel.org/all/a0caa289-ca02-48eb-9bf2-d86fd47b71f4@redhat.com/ Reported-by: Damien Le Moal damien.lemoal@opensource.wdc.com Closes: https://lore.kernel.org/all/f9ff999a-e170-b66b-7caf-293f2b147ac2@opensource.... Suggested-by: Dave Chinner david@fromorbit.com Tested-by: Xiubo Li xiubli@redhat.com Cc: Christoph Hellwig hch@infradead.org Cc: Alexander Potapenko glider@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- lib/stackdepot.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -256,10 +256,10 @@ depot_stack_handle_t depot_save_stack(st /* * Zero out zone modifiers, as we don't have specific zone * requirements. Keep the flags related to allocation in atomic - * contexts and I/O. + * contexts, I/O, nolockdep. */ alloc_flags &= ~GFP_ZONEMASK; - alloc_flags &= (GFP_ATOMIC | GFP_KERNEL); + alloc_flags &= (GFP_ATOMIC | GFP_KERNEL | __GFP_NOLOCKDEP); alloc_flags |= __GFP_NOWARN; page = alloc_pages(alloc_flags, STACK_ALLOC_ORDER); if (page)