[syzbot] [keyrings?] [lsm?] [ext4?] possible deadlock in keyring_clear (2)
From: syzbot
Date: Sun Sep 22 2024 - 06:53:37 EST
Hello,
syzbot found the following issue on:
HEAD commit: 2f27fce67173 Merge tag 'sound-6.12-rc1' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=118d7500580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1cb2f9a0593f5374
dashboard link: https://syzkaller.appspot.com/bug?extid=1b2d1134e0b675176a15
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1511c69f980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16107fc7980000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-2f27fce6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9f657bfdbb07/vmlinux-2f27fce6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b3ee0fec5f83/bzImage-2f27fce6.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/96f591b14f71/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1b2d1134e0b675176a15@xxxxxxxxxxxxxxxxxxxxxxxxx
======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-04557-g2f27fce67173 #0 Not tainted
------------------------------------------------------
kswapd0/79 is trying to acquire lock:
ffff88803c9e2e98 (&type->lock_class){+.+.}-{3:3}, at: keyring_clear+0xb2/0x350 security/keys/keyring.c:1655
but task is already holding lock:
ffffffff8ea30460 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6821 [inline]
ffffffff8ea30460 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3720 mm/vmscan.c:7203
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
__fs_reclaim_acquire mm/page_alloc.c:3825 [inline]
fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3839
might_alloc include/linux/sched/mm.h:334 [inline]
slab_pre_alloc_hook mm/slub.c:3940 [inline]
slab_alloc_node mm/slub.c:4018 [inline]
__kmalloc_cache_noprof+0x3d/0x2c0 mm/slub.c:4185
kmalloc_noprof include/linux/slab.h:690 [inline]
kzalloc_noprof include/linux/slab.h:816 [inline]
assoc_array_insert+0xfe/0x33e0 lib/assoc_array.c:980
__key_link_begin+0xe5/0x1f0 security/keys/keyring.c:1314
__key_create_or_update+0x570/0xc70 security/keys/key.c:874
key_create_or_update+0x42/0x60 security/keys/key.c:1018
x509_load_certificate_list+0x149/0x270 crypto/asymmetric_keys/x509_loader.c:31
do_one_initcall+0x248/0x880 init/main.c:1269
do_initcall_level+0x157/0x210 init/main.c:1331
do_initcalls+0x3f/0x80 init/main.c:1347
kernel_init_freeable+0x435/0x5d0 init/main.c:1580
kernel_init+0x1d/0x2b0 init/main.c:1469
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #0 (&type->lock_class){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3158 [inline]
check_prevs_add kernel/locking/lockdep.c:3277 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
__lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
down_write+0x99/0x220 kernel/locking/rwsem.c:1579
keyring_clear+0xb2/0x350 security/keys/keyring.c:1655
fscrypt_put_master_key+0xc8/0x190 fs/crypto/keyring.c:79
put_crypt_info+0x275/0x320 fs/crypto/keysetup.c:548
fscrypt_put_encryption_info+0x40/0x60 fs/crypto/keysetup.c:753
ext4_clear_inode+0x15b/0x1c0 fs/ext4/super.c:1524
ext4_evict_inode+0xabc/0xf50 fs/ext4/inode.c:318
evict+0x4e8/0x9b0 fs/inode.c:731
__dentry_kill+0x20d/0x630 fs/dcache.c:615
shrink_kill+0xa9/0x2c0 fs/dcache.c:1060
shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1087
prune_dcache_sb+0x10f/0x180 fs/dcache.c:1168
super_cache_scan+0x34f/0x4b0 fs/super.c:221
do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
shrink_one+0x43b/0x850 mm/vmscan.c:4795
shrink_many mm/vmscan.c:4856 [inline]
lru_gen_shrink_node mm/vmscan.c:4934 [inline]
shrink_node+0x3799/0x3de0 mm/vmscan.c:5914
kswapd_shrink_node mm/vmscan.c:6742 [inline]
balance_pgdat mm/vmscan.c:6934 [inline]
kswapd+0x1cbc/0x3720 mm/vmscan.c:7203
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&type->lock_class);
lock(fs_reclaim);
lock(&type->lock_class);
*** DEADLOCK ***
2 locks held by kswapd0/79:
#0: ffffffff8ea30460 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6821 [inline]
#0: ffffffff8ea30460 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3720 mm/vmscan.c:7203
#1: ffff88803ba840e0 (&type->s_umount_key#32){++++}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline]
#1: ffff88803ba840e0 (&type->s_umount_key#32){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196
stack backtrace:
CPU: 0 UID: 0 PID: 79 Comm: kswapd0 Not tainted 6.11.0-syzkaller-04557-g2f27fce67173 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:93 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
check_prev_add kernel/locking/lockdep.c:3158 [inline]
check_prevs_add kernel/locking/lockdep.c:3277 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
__lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
down_write+0x99/0x220 kernel/locking/rwsem.c:1579
keyring_clear+0xb2/0x350 security/keys/keyring.c:1655
fscrypt_put_master_key+0xc8/0x190 fs/crypto/keyring.c:79
put_crypt_info+0x275/0x320 fs/crypto/keysetup.c:548
fscrypt_put_encryption_info+0x40/0x60 fs/crypto/keysetup.c:753
ext4_clear_inode+0x15b/0x1c0 fs/ext4/super.c:1524
ext4_evict_inode+0xabc/0xf50 fs/ext4/inode.c:318
evict+0x4e8/0x9b0 fs/inode.c:731
__dentry_kill+0x20d/0x630 fs/dcache.c:615
shrink_kill+0xa9/0x2c0 fs/dcache.c:1060
shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1087
prune_dcache_sb+0x10f/0x180 fs/dcache.c:1168
super_cache_scan+0x34f/0x4b0 fs/super.c:221
do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
shrink_one+0x43b/0x850 mm/vmscan.c:4795
shrink_many mm/vmscan.c:4856 [inline]
lru_gen_shrink_node mm/vmscan.c:4934 [inline]
shrink_node+0x3799/0x3de0 mm/vmscan.c:5914
kswapd_shrink_node mm/vmscan.c:6742 [inline]
balance_pgdat mm/vmscan.c:6934 [inline]
kswapd+0x1cbc/0x3720 mm/vmscan.c:7203
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
---
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