possible deadlock in __blk_crypto_evict_key

Status: upstream: reported on 2026/09/04 20:10
Subsystems: fscrypt
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+20d60aafd9a0d1f2a380@syzkaller.appspotmail.com
First crash: 49d, last: 39d
▶ ▼ ✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision
5495b6f3 repro-c 💥 possible deadlock in __blk_crypto_evict_key 2026/10/04 10:27 2026/10/04 10:27 2026/10/04 13:22 57bbd979
6ca37aef repro-c 💥 possible deadlock in __blk_crypto_evict_key 2026/10/02 14:29 2026/10/02 14:29 2026/10/02 17:12 57bbd979
bd7f1e67 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ possible deadlock in __blk_crypto_evict_key 2026/09/02 00:04 2026/09/02 00:04 2026/09/02 00:44 587f6b29
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [crypto?] possible deadlock in __blk_crypto_evict_key 1 (2) 2026/10/06 09:24

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kswapd0/77 is trying to acquire lock:
ffff8880001428c8 (&profile->lock){++++}-{4:4}, at: blk_crypto_hw_enter block/blk-crypto-profile.c:55 [inline]
ffff8880001428c8 (&profile->lock){++++}-{4:4}, at: __blk_crypto_evict_key+0x111/0x5e0 block/blk-crypto-profile.c:359

but task is already holding lock:
ffffffff8ee924c0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7177 [inline]
ffffffff8ee924c0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xa08/0x32c0 mm/vmscan.c:7555

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4375 [inline]
       fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4389
       might_alloc include/linux/sched/mm.h:316 [inline]
       slab_pre_alloc_hook mm/slub.c:4636 [inline]
       slab_alloc_node mm/slub.c:4974 [inline]
       __do_kmalloc_node mm/slub.c:5413 [inline]
       __kmalloc_noprof+0xbc/0x720 mm/slub.c:5439
       _kmalloc_noprof include/linux/slab.h:995 [inline]
       _kzalloc_noprof include/linux/slab.h:1312 [inline]
       adiantum_setkey+0x139/0x620 crypto/adiantum.c:129
       crypto_skcipher_setkey+0x2a3/0x460 crypto/skcipher.c:422
       crypto_sync_skcipher_setkey include/crypto/skcipher.h:621 [inline]
       blk_crypto_fallback_keyslot_program+0x1ad/0x440 block/blk-crypto-fallback.c:122
       blk_crypto_get_keyslot+0x941/0x1070 block/blk-crypto-profile.c:295
       blk_crypto_fallback_encrypt_bio block/blk-crypto-fallback.c:362 [inline]
       blk_crypto_fallback_bio_prep+0x424/0x1b40 block/blk-crypto-fallback.c:505
       blk_crypto_submit_bio include/linux/blk-crypto.h:211 [inline]
       f2fs_submit_write_bio+0x11b/0x2e0 fs/f2fs/data.c:575
       __submit_merged_bio+0x258/0x6a0 fs/f2fs/data.c:590
       __f2fs_submit_merged_write fs/f2fs/data.c:682 [inline]
       __submit_merged_write_cond+0x3c9/0x4e0 fs/f2fs/data.c:706
       f2fs_submit_merged_write_cond fs/f2fs/data.c:731 [inline]
       f2fs_write_cache_pages fs/f2fs/data.c:3495 [inline]
       __f2fs_write_data_pages fs/f2fs/data.c:3603 [inline]
       f2fs_write_data_pages+0x2a27/0x36f0 fs/f2fs/data.c:3641
       do_writepages+0x338/0x560 mm/page-writeback.c:2560
       filemap_writeback mm/filemap.c:387 [inline]
       filemap_fdatawrite_range mm/filemap.c:412 [inline]
       filemap_write_and_wait_range+0x335/0x3f0 mm/filemap.c:684
       __iomap_dio_rw+0x8a3/0x1c40 fs/iomap/direct-io.c:739
       f2fs_dio_read_iter fs/f2fs/file.c:5233 [inline]
       f2fs_file_read_iter+0x60b/0x940 fs/f2fs/file.c:5296
       copy_splice_read+0x5ff/0xaa0 fs/splice.c:362
       do_splice_read fs/splice.c:979 [inline]
       splice_direct_to_actor+0x4b6/0xcb0 fs/splice.c:1084
       do_splice_direct_actor fs/splice.c:1202 [inline]
       do_splice_direct+0x195/0x290 fs/splice.c:1228
       do_sendfile+0x52e/0x7c0 fs/read_write.c:1371
       __do_sys_sendfile64 fs/read_write.c:1432 [inline]
       __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1418
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&profile->lock){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3209 [inline]
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
       lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
       down_write+0x96/0x200 kernel/locking/rwsem.c:1631
       blk_crypto_hw_enter block/blk-crypto-profile.c:55 [inline]
       __blk_crypto_evict_key+0x111/0x5e0 block/blk-crypto-profile.c:359
       blk_crypto_evict_key+0x230/0x3c0 block/blk-crypto.c:443
       fscrypt_destroy_inline_crypt_key+0x1b9/0x260 fs/crypto/block.c:164
       fscrypt_destroy_prepared_key fs/crypto/keysetup.c:173 [inline]
       put_crypt_info+0x110/0x2f0 fs/crypto/keysetup.c:560
       fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:786
       f2fs_evict_inode+0x1c9f/0x21f0 fs/f2fs/inode.c:1105
       evict+0x624/0xb50 fs/inode.c:822
       dispose_list fs/inode.c:864 [inline]
       prune_icache_sb+0x223/0x2d0 fs/inode.c:1011
       super_cache_scan+0x3f5/0x500 fs/super.c:240
       do_shrink_slab+0x6d0/0x10e0 mm/shrinker.c:443
       shrink_slab_memcg mm/shrinker.c:560 [inline]
       shrink_slab+0x838/0x1220 mm/shrinker.c:638
       shrink_one+0x2a2/0x730 mm/vmscan.c:5119
       shrink_many mm/vmscan.c:5180 [inline]
       lru_gen_shrink_node mm/vmscan.c:5258 [inline]
       shrink_node+0x35d0/0x3e30 mm/vmscan.c:6247
       kswapd_shrink_node mm/vmscan.c:7101 [inline]
       balance_pgdat mm/vmscan.c:7279 [inline]
       kswapd+0x185e/0x32c0 mm/vmscan.c:7555
       kthread+0x38b/0x480 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&profile->lock);
                               lock(fs_reclaim);
  lock(&profile->lock);

 *** DEADLOCK ***

locks held by kswapd0/77: 2, last CPU#0:
 #0: ffffffff8ee924c0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7177 [inline]
 #0: ffffffff8ee924c0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xa08/0x32c0 mm/vmscan.c:7555
 #1: ffff8880358700e8 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:688 [inline]
 #1: ffff8880358700e8 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_cache_scan+0x94/0x500 fs/super.c:213

stack backtrace:
CPU: 0 UID: 0 PID: 77 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087
 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219
 check_prev_add kernel/locking/lockdep.c:3209 [inline]
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 down_write+0x96/0x200 kernel/locking/rwsem.c:1631
 blk_crypto_hw_enter block/blk-crypto-profile.c:55 [inline]
 __blk_crypto_evict_key+0x111/0x5e0 block/blk-crypto-profile.c:359
 blk_crypto_evict_key+0x230/0x3c0 block/blk-crypto.c:443
 fscrypt_destroy_inline_crypt_key+0x1b9/0x260 fs/crypto/block.c:164
 fscrypt_destroy_prepared_key fs/crypto/keysetup.c:173 [inline]
 put_crypt_info+0x110/0x2f0 fs/crypto/keysetup.c:560
 fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:786
 f2fs_evict_inode+0x1c9f/0x21f0 fs/f2fs/inode.c:1105
 evict+0x624/0xb50 fs/inode.c:822
 dispose_list fs/inode.c:864 [inline]
 prune_icache_sb+0x223/0x2d0 fs/inode.c:1011
 super_cache_scan+0x3f5/0x500 fs/super.c:240
 do_shrink_slab+0x6d0/0x10e0 mm/shrinker.c:443
 shrink_slab_memcg mm/shrinker.c:560 [inline]
 shrink_slab+0x838/0x1220 mm/shrinker.c:638
 shrink_one+0x2a2/0x730 mm/vmscan.c:5119
 shrink_many mm/vmscan.c:5180 [inline]
 lru_gen_shrink_node mm/vmscan.c:5258 [inline]
 shrink_node+0x35d0/0x3e30 mm/vmscan.c:6247
 kswapd_shrink_node mm/vmscan.c:7101 [inline]
 balance_pgdat mm/vmscan.c:7279 [inline]
 kswapd+0x185e/0x32c0 mm/vmscan.c:7555
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/11 09:57 upstream 50d05c7c76c9 1fe56c0a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __blk_crypto_evict_key
2026/09/11 03:02 upstream 50d05c7c76c9 1fe56c0a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __blk_crypto_evict_key
2026/09/11 01:03 upstream 50d05c7c76c9 1fe56c0a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __blk_crypto_evict_key
2026/09/04 09:49 upstream 8ab1afb2eb24 801f0966 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __blk_crypto_evict_key
2026/08/31 20:11 upstream cee9395acd80 00e9c810 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __blk_crypto_evict_key
2026/08/31 20:10 upstream cee9395acd80 00e9c810 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __blk_crypto_evict_key
2026/08/31 20:07 upstream cee9395acd80 00e9c810 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in __blk_crypto_evict_key
* Struck through repros no longer work on HEAD.