[syzbot] [ocfs2?] possible deadlock in ocfs2_page_mkwrite

From: syzbot
Date: Thu Sep 12 2024 - 05:35:55 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 8d8d276ba2fb Merge tag 'trace-v6.11-rc6' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=119fa477980000
kernel config: https://syzkaller.appspot.com/x/.config?x=61d235cb8d15001c
dashboard link: https://syzkaller.appspot.com/bug?extid=2e6495950edcf7fbfccf
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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-8d8d276b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d23708af23a4/vmlinux-8d8d276b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1aed2837c105/bzImage-8d8d276b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2e6495950edcf7fbfccf@xxxxxxxxxxxxxxxxxxxxxxxxx

loop0: detected capacity change from 0 to 32768
=======================================================
WARNING: The mand mount option has been deprecated and
and is ignored by this kernel. Remove the mand
option from the mount to silence this warning.
=======================================================
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc7-syzkaller-00020-g8d8d276ba2fb #0 Not tainted
------------------------------------------------------
syz.0.0/5113 is trying to acquire lock:
ffff88804bc43f60 (&oi->ip_alloc_sem){++++}-{3:3}, at: ocfs2_page_mkwrite+0x347/0xed0 fs/ocfs2/mmap.c:142

but task is already holding lock:
ffff88804ac2e518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x19b/0x480 mm/memory.c:3142

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (sb_pagefaults){.+.+}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1676 [inline]
sb_start_pagefault include/linux/fs.h:1841 [inline]
ocfs2_page_mkwrite+0x223/0xed0 fs/ocfs2/mmap.c:122
do_page_mkwrite+0x19b/0x480 mm/memory.c:3142
wp_page_shared mm/memory.c:3545 [inline]
do_wp_page+0x23d9/0x52f0 mm/memory.c:3695
handle_pte_fault+0x115a/0x6fc0 mm/memory.c:5537
__handle_mm_fault mm/memory.c:5664 [inline]
handle_mm_fault+0x1109/0x1bc0 mm/memory.c:5832
do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:65
copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline]
copy_to_user_iter lib/iov_iter.c:25 [inline]
iterate_ubuf include/linux/iov_iter.h:29 [inline]
iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x26b/0x1960 lib/iov_iter.c:185
copy_to_iter include/linux/uio.h:196 [inline]
get_random_bytes_user+0x1e5/0x420 drivers/char/random.c:464
__do_sys_getrandom drivers/char/random.c:1406 [inline]
__se_sys_getrandom drivers/char/random.c:1380 [inline]
__x64_sys_getrandom+0x152/0x250 drivers/char/random.c:1380
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&mm->mmap_lock){++++}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
__might_fault+0xc6/0x120 mm/memory.c:6387
_inline_copy_to_user include/linux/uaccess.h:176 [inline]
_copy_to_user+0x2a/0xb0 lib/usercopy.c:26
copy_to_user include/linux/uaccess.h:209 [inline]
fiemap_fill_next_extent+0x235/0x410 fs/ioctl.c:145
ocfs2_fiemap+0x9f1/0xf80 fs/ocfs2/extent_map.c:796
ioctl_fiemap fs/ioctl.c:220 [inline]
do_vfs_ioctl+0x1c07/0x2e50 fs/ioctl.c:841
__do_sys_ioctl fs/ioctl.c:905 [inline]
__se_sys_ioctl+0x81/0x170 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&oi->ip_alloc_sem){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3133 [inline]
check_prevs_add kernel/locking/lockdep.c:3252 [inline]
validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
__lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
down_write+0x99/0x220 kernel/locking/rwsem.c:1579
ocfs2_page_mkwrite+0x347/0xed0 fs/ocfs2/mmap.c:142
do_page_mkwrite+0x19b/0x480 mm/memory.c:3142
wp_page_shared mm/memory.c:3545 [inline]
do_wp_page+0x23d9/0x52f0 mm/memory.c:3695
handle_pte_fault+0x115a/0x6fc0 mm/memory.c:5537
__handle_mm_fault mm/memory.c:5664 [inline]
handle_mm_fault+0x1109/0x1bc0 mm/memory.c:5832
do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:65
copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline]
copy_to_user_iter lib/iov_iter.c:25 [inline]
iterate_ubuf include/linux/iov_iter.h:29 [inline]
iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x26b/0x1960 lib/iov_iter.c:185
copy_to_iter include/linux/uio.h:196 [inline]
get_random_bytes_user+0x1e5/0x420 drivers/char/random.c:464
__do_sys_getrandom drivers/char/random.c:1406 [inline]
__se_sys_getrandom drivers/char/random.c:1380 [inline]
__x64_sys_getrandom+0x152/0x250 drivers/char/random.c:1380
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
&oi->ip_alloc_sem --> &mm->mmap_lock --> sb_pagefaults

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
rlock(sb_pagefaults);
lock(&mm->mmap_lock);
lock(sb_pagefaults);
lock(&oi->ip_alloc_sem);

*** DEADLOCK ***

2 locks held by syz.0.0/5113:
#0: ffff888040731e18 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:163 [inline]
#0: ffff888040731e18 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5869 [inline]
#0: ffff888040731e18 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5929
#1: ffff88804ac2e518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x19b/0x480 mm/memory.c:3142

stack backtrace:
CPU: 0 UID: 0 PID: 5113 Comm: syz.0.0 Not tainted 6.11.0-rc7-syzkaller-00020-g8d8d276ba2fb #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
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2186
check_prev_add kernel/locking/lockdep.c:3133 [inline]
check_prevs_add kernel/locking/lockdep.c:3252 [inline]
validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
__lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
down_write+0x99/0x220 kernel/locking/rwsem.c:1579
ocfs2_page_mkwrite+0x347/0xed0 fs/ocfs2/mmap.c:142
do_page_mkwrite+0x19b/0x480 mm/memory.c:3142
wp_page_shared mm/memory.c:3545 [inline]
do_wp_page+0x23d9/0x52f0 mm/memory.c:3695
handle_pte_fault+0x115a/0x6fc0 mm/memory.c:5537
__handle_mm_fault mm/memory.c:5664 [inline]
handle_mm_fault+0x1109/0x1bc0 mm/memory.c:5832
do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:71
Code: 75 f1 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 <f3> a4 c3 cc cc cc cc 48 89 c8 48 c1 e9 03 83 e0 07 f3 48 a5 89 c1
RSP: 0018:ffffc9000b62faf8 EFLAGS: 00050246
RAX: ffffffff84b01901 RBX: 0000000000000040 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffc9000b62fd40 RDI: 0000000020000240
RBP: ffffc9000b62fc70 R08: ffffc9000b62fd7f R09: 1ffff920016c5faf
R10: dffffc0000000000 R11: fffff520016c5fb0 R12: 1ffff920016c5fc9
R13: 0000000020000240 R14: ffffc9000b62fe48 R15: ffffc9000b62fd40
copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline]
copy_to_user_iter lib/iov_iter.c:25 [inline]
iterate_ubuf include/linux/iov_iter.h:29 [inline]
iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x26b/0x1960 lib/iov_iter.c:185
copy_to_iter include/linux/uio.h:196 [inline]
get_random_bytes_user+0x1e5/0x420 drivers/char/random.c:464
__do_sys_getrandom drivers/char/random.c:1406 [inline]
__se_sys_getrandom drivers/char/random.c:1380 [inline]
__x64_sys_getrandom+0x152/0x250 drivers/char/random.c:1380
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f375117def9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3751e92038 EFLAGS: 00000246 ORIG_RAX: 000000000000013e
RAX: ffffffffffffffda RBX: 00007f3751335f80 RCX: 00007f375117def9
RDX: 0000000000000000 RSI: 00000000ffffff9a RDI: 0000000020000240
RBP: 00007f37511f09f6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3751335f80 R15: 00007fff8387faa8
</TASK>
----------------
Code disassembly (best guess):
0: 75 f1 jne 0xfffffff3
2: c3 ret
3: cc int3
4: cc int3
5: cc int3
6: cc int3
7: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
e: 00 00
10: 48 8b 06 mov (%rsi),%rax
13: 48 89 07 mov %rax,(%rdi)
16: 48 83 c6 08 add $0x8,%rsi
1a: 48 83 c7 08 add $0x8,%rdi
1e: 83 e9 08 sub $0x8,%ecx
21: 74 df je 0x2
23: 83 f9 08 cmp $0x8,%ecx
26: 73 e8 jae 0x10
28: eb c9 jmp 0xfffffff3
* 2a: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
2c: c3 ret
2d: cc int3
2e: cc int3
2f: cc int3
30: cc int3
31: 48 89 c8 mov %rcx,%rax
34: 48 c1 e9 03 shr $0x3,%rcx
38: 83 e0 07 and $0x7,%eax
3b: f3 48 a5 rep movsq %ds:(%rsi),%es:(%rdi)
3e: 89 c1 mov %eax,%ecx

---
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Next message: Christophe Leroy: "Re: [PATCH 1/2] powerpc/entry: convert to common and generic entry"
Previous message: syzbot: "[syzbot] [ocfs2?] possible deadlock in ocfs2_write_begin_nolock"
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