[syzbot] [udf?] possible deadlock in udf_file_write_iter

From: syzbot
Date: Wed May 29 2024 - 16:41:41 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 54f71b0369c9 Merge tag 'rtc-6.10' of git://git.kernel.org/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11b9197c980000
kernel config: https://syzkaller.appspot.com/x/.config?x=e70c03a304f3c3ef
dashboard link: https://syzkaller.appspot.com/bug?extid=b8bf17b888663bcdee61
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-54f71b03.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5bc3c5654135/vmlinux-54f71b03.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d88013021348/bzImage-54f71b03.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b8bf17b888663bcdee61@xxxxxxxxxxxxxxxxxxxxxxxxx

WARNING: possible circular locking dependency detected
6.9.0-syzkaller-12333-g54f71b0369c9 #0 Not tainted
------------------------------------------------------
syz-executor.3/7881 is trying to acquire lock:
ffffffff8dd3a8a0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:334 [inline]
ffffffff8dd3a8a0 (fs_reclaim){+.+.}-{0:0}, at: prepare_alloc_pages.constprop.0+0x155/0x560 mm/page_alloc.c:4431

but task is already holding lock:
ffff888012624ac0 (mapping.invalidate_lock#8){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:836 [inline]
ffff888012624ac0 (mapping.invalidate_lock#8){++++}-{3:3}, at: udf_file_write_iter+0x5c2/0x740 fs/udf/file.c:104

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (mapping.invalidate_lock#8){++++}-{3:3}:
down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
filemap_invalidate_lock include/linux/fs.h:836 [inline]
udf_setsize+0x256/0x1180 fs/udf/inode.c:1253
udf_evict_inode+0x361/0x590 fs/udf/inode.c:144
evict+0x2ed/0x6c0 fs/inode.c:667
iput_final fs/inode.c:1741 [inline]
iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
iput+0x5c/0x80 fs/inode.c:1757
dentry_unlink_inode+0x295/0x480 fs/dcache.c:400
__dentry_kill+0x1d0/0x600 fs/dcache.c:603
shrink_kill fs/dcache.c:1048 [inline]
shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075
prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156
super_cache_scan+0x32a/0x550 fs/super.c:221
do_shrink_slab+0x44f/0x11c0 mm/shrinker.c:435
shrink_slab_memcg mm/shrinker.c:548 [inline]
shrink_slab+0xa87/0x1310 mm/shrinker.c:626
shrink_one+0x493/0x7c0 mm/vmscan.c:4790
shrink_many mm/vmscan.c:4851 [inline]
lru_gen_shrink_node+0x89f/0x1750 mm/vmscan.c:4951
shrink_node mm/vmscan.c:5910 [inline]
kswapd_shrink_node mm/vmscan.c:6720 [inline]
balance_pgdat+0x1105/0x1970 mm/vmscan.c:6911
kswapd+0x5ea/0xbf0 mm/vmscan.c:7180
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (fs_reclaim){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
__fs_reclaim_acquire mm/page_alloc.c:3783 [inline]
fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3797
might_alloc include/linux/sched/mm.h:334 [inline]
prepare_alloc_pages.constprop.0+0x155/0x560 mm/page_alloc.c:4431
__alloc_pages_noprof+0x194/0x2460 mm/page_alloc.c:4649
alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2265
folio_alloc_noprof+0x1e/0xc0 mm/mempolicy.c:2343
filemap_alloc_folio_noprof+0x3ba/0x490 mm/filemap.c:1008
__filemap_get_folio+0x51e/0xa80 mm/filemap.c:1950
udf_expand_file_adinicb+0xe9/0x940 fs/udf/inode.c:358
udf_file_write_iter+0x5ca/0x740 fs/udf/file.c:105
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0x6b6/0x1140 fs/read_write.c:590
ksys_write+0x12f/0x260 fs/read_write.c:643
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(mapping.invalidate_lock#8);
lock(fs_reclaim);
lock(mapping.invalidate_lock#8);
lock(fs_reclaim);

*** DEADLOCK ***

4 locks held by syz-executor.3/7881:
#0: ffff88801d50fcc8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xeb/0x180 fs/file.c:1191
#1: ffff88801b398420 (sb_writers#19){.+.+}-{0:0}, at: ksys_write+0x12f/0x260 fs/read_write.c:643
#2: ffff888012624920 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:791 [inline]
#2: ffff888012624920 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: udf_file_write_iter+0x73/0x740 fs/udf/file.c:95
#3: ffff888012624ac0 (mapping.invalidate_lock#8){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:836 [inline]
#3: ffff888012624ac0 (mapping.invalidate_lock#8){++++}-{3:3}, at: udf_file_write_iter+0x5c2/0x740 fs/udf/file.c:104

stack backtrace:
CPU: 3 PID: 7881 Comm: syz-executor.3 Not tainted 6.9.0-syzkaller-12333-g54f71b0369c9 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
__fs_reclaim_acquire mm/page_alloc.c:3783 [inline]
fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3797
might_alloc include/linux/sched/mm.h:334 [inline]
prepare_alloc_pages.constprop.0+0x155/0x560 mm/page_alloc.c:4431
__alloc_pages_noprof+0x194/0x2460 mm/page_alloc.c:4649
alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2265
folio_alloc_noprof+0x1e/0xc0 mm/mempolicy.c:2343
filemap_alloc_folio_noprof+0x3ba/0x490 mm/filemap.c:1008
__filemap_get_folio+0x51e/0xa80 mm/filemap.c:1950
udf_expand_file_adinicb+0xe9/0x940 fs/udf/inode.c:358
udf_file_write_iter+0x5ca/0x740 fs/udf/file.c:105
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0x6b6/0x1140 fs/read_write.c:590
ksys_write+0x12f/0x260 fs/read_write.c:643
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7313579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f5f055ac EFLAGS: 00000292 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000020000a80
RDX: 0000000000000173 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 10 06 adc %al,(%rsi)
2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
6: 10 07 adc %al,(%rdi)
8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
c: 10 08 adc %cl,(%rax)
e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
1e: 00 51 52 add %dl,0x52(%rcx)
21: 55 push %rbp
22: 89 e5 mov %esp,%ebp
24: 0f 34 sysenter
26: cd 80 int $0x80
* 28: 5d pop %rbp <-- trapping instruction
29: 5a pop %rdx
2a: 59 pop %rcx
2b: c3 ret
2c: 90 nop
2d: 90 nop
2e: 90 nop
2f: 90 nop
30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi

---
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Next message: Adam Williamson: "Re: Intermittent inability to type in graphical Plymouth on UEFI VMs since kernel 6.9"
Previous message: syzbot: "[syzbot] [fscrypt?] WARNING in fscrypt_fname_siphash"
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