[v6.1] possible deadlock in sys_mbind

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 48d525b0e463 Linux 6.1.103
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16ba9f75980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1a8b264edc2488f
dashboard link: https://syzkaller.appspot.com/bug?extid=6f306496112a9972586e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/06cea92ea31f/disk-48d525b0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/83efa486ea4e/vmlinux-48d525b0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d7f6fd55583d/Image-48d525b0.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6f3064...@syzkaller.appspotmail.com

REISERFS (device loop1): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.1.103-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.341/5749 is trying to acquire lock:
ffff0000edf35090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: do_mbind mm/mempolicy.c:1302 [inline]
ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: kernel_mbind mm/mempolicy.c:1481 [inline]
ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: __do_sys_mbind mm/mempolicy.c:1558 [inline]
ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: __se_sys_mbind mm/mempolicy.c:1554 [inline]
ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: __arm64_sys_mbind+0x5f4/0xb40 mm/mempolicy.c:1554

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock){++++}-{3:3}:
__might_fault+0xc4/0x124 mm/memory.c:5835
reiserfs_ioctl+0x10c/0x454 fs/reiserfs/ioctl.c:96
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (&sbi->lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
__mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
map_block_for_writepage fs/reiserfs/inode.c:2388 [inline]
reiserfs_write_full_page fs/reiserfs/inode.c:2585 [inline]
reiserfs_writepage+0x7b0/0x2d40 fs/reiserfs/inode.c:2737
writeout mm/migrate.c:890 [inline]
fallback_migrate_folio mm/migrate.c:914 [inline]
move_to_new_folio+0x624/0xc24 mm/migrate.c:963
__unmap_and_move mm/migrate.c:1124 [inline]
unmap_and_move mm/migrate.c:1196 [inline]
migrate_pages+0x1968/0x3644 mm/migrate.c:1473
do_mbind mm/mempolicy.c:1334 [inline]
kernel_mbind mm/mempolicy.c:1481 [inline]
__do_sys_mbind mm/mempolicy.c:1558 [inline]
__se_sys_mbind mm/mempolicy.c:1554 [inline]
__arm64_sys_mbind+0x8fc/0xb40 mm/mempolicy.c:1554
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&mm->mmap_lock);
lock(&sbi->lock);
lock(&mm->mmap_lock);
lock(&sbi->lock);

*** DEADLOCK ***

1 lock held by syz.1.341/5749:
#0: ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: do_mbind mm/mempolicy.c:1302 [inline]
#0: ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: kernel_mbind mm/mempolicy.c:1481 [inline]
#0: ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: __do_sys_mbind mm/mempolicy.c:1558 [inline]
#0: ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: __se_sys_mbind mm/mempolicy.c:1554 [inline]
#0: ffff0000ce6aed48 (&mm->mmap_lock){++++}-{3:3}, at: __arm64_sys_mbind+0x5f4/0xb40 mm/mempolicy.c:1554

stack backtrace:
CPU: 1 PID: 5749 Comm: syz.1.341 Not tainted 6.1.103-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call trace:
dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2048
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2170
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
__mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
map_block_for_writepage fs/reiserfs/inode.c:2388 [inline]
reiserfs_write_full_page fs/reiserfs/inode.c:2585 [inline]
reiserfs_writepage+0x7b0/0x2d40 fs/reiserfs/inode.c:2737
writeout mm/migrate.c:890 [inline]
fallback_migrate_folio mm/migrate.c:914 [inline]
move_to_new_folio+0x624/0xc24 mm/migrate.c:963
__unmap_and_move mm/migrate.c:1124 [inline]
unmap_and_move mm/migrate.c:1196 [inline]
migrate_pages+0x1968/0x3644 mm/migrate.c:1473
do_mbind mm/mempolicy.c:1334 [inline]
kernel_mbind mm/mempolicy.c:1481 [inline]
__do_sys_mbind mm/mempolicy.c:1558 [inline]
__se_sys_mbind mm/mempolicy.c:1554 [inline]
__arm64_sys_mbind+0x8fc/0xb40 mm/mempolicy.c:1554
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585


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