[syzbot] possible deadlock in ext4_evict_inode (2)

From: syzbot
Date: Wed Sep 21 2022 - 05:25:49 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 60891ec99e14 Merge tag 'for-6.0-rc6-tag' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16bd5654880000
kernel config: https://syzkaller.appspot.com/x/.config?x=c221af36f6d1d811
dashboard link: https://syzkaller.appspot.com/bug?extid=b6ad7e348919e233ee7f
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/26088fcec75b/disk-60891ec9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/71fa9bd9b624/vmlinux-60891ec9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6ad7e348919e233ee7f@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc6-syzkaller-00009-g60891ec99e14 #0 Not tainted
------------------------------------------------------
syz-executor.5/29299 is trying to acquire lock:
ffff88814afb8650 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1826 [inline]
ffff88814afb8650 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1948 [inline]
ffff88814afb8650 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x4b7/0x1010 fs/ext4/inode.c:240

but task is already holding lock:
ffff88814afbabd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x212/0x1220 fs/ext4/migrate.c:437

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&sbi->s_writepages_rwsem){++++}-{0:0}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
percpu_down_write+0x50/0x330 kernel/locking/percpu-rwsem.c:221
ext4_ind_migrate+0x262/0x730 fs/ext4/migrate.c:624
ext4_ioctl_setflags fs/ext4/ioctl.c:694 [inline]
ext4_fileattr_set+0xe53/0x17d0 fs/ext4/ioctl.c:1001
vfs_fileattr_set+0x8be/0xd20 fs/ioctl.c:696
ioctl_setflags fs/ioctl.c:728 [inline]
do_vfs_ioctl+0x1d26/0x29a0 fs/ioctl.c:839
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #2 (&sb->s_type->i_mutex_key#8){++++}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
down_read+0x39/0x50 kernel/locking/rwsem.c:1499
inode_lock_shared include/linux/fs.h:766 [inline]
ext4_bmap+0x55/0x410 fs/ext4/inode.c:3157
bmap+0xa1/0xd0 fs/inode.c:1799
jbd2_journal_bmap fs/jbd2/journal.c:971 [inline]
__jbd2_journal_erase fs/jbd2/journal.c:1784 [inline]
jbd2_journal_flush+0x5d0/0xca0 fs/jbd2/journal.c:2490
ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline]
__ext4_ioctl fs/ext4/ioctl.c:1586 [inline]
ext4_ioctl+0x31ad/0x5410 fs/ext4/ioctl.c:1606
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
__mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
mutex_lock_io_nested+0x43/0x60 kernel/locking/mutex.c:833
__jbd2_log_wait_for_space+0x21d/0x6f0 fs/jbd2/checkpoint.c:110
add_transaction_credits+0x916/0xbd0 fs/jbd2/transaction.c:298
start_this_handle+0x744/0x1670 fs/jbd2/transaction.c:422
jbd2__journal_start+0x2ca/0x5b0 fs/jbd2/transaction.c:520
__ext4_journal_start_sb+0x111/0x1d0 fs/ext4/ext4_jbd2.c:105
__ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
ext4_evict_inode+0x8e7/0x1010 fs/ext4/inode.c:251
evict+0x2a4/0x620 fs/inode.c:665
do_unlinkat+0x4f2/0x940 fs/namei.c:4304
__do_sys_unlink fs/namei.c:4345 [inline]
__se_sys_unlink fs/namei.c:4343 [inline]
__x64_sys_unlink+0x45/0x50 fs/namei.c:4343
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sb_internal){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain+0x1873/0x6c00 kernel/locking/lockdep.c:3829
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5053
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
percpu_down_read+0x44/0x190 include/linux/percpu-rwsem.h:51
__sb_start_write include/linux/fs.h:1826 [inline]
sb_start_intwrite include/linux/fs.h:1948 [inline]
ext4_evict_inode+0x4b7/0x1010 fs/ext4/inode.c:240
evict+0x2a4/0x620 fs/inode.c:665
ext4_ext_migrate+0xf3a/0x1220 fs/ext4/migrate.c:587
__ext4_ioctl fs/ext4/ioctl.c:1388 [inline]
ext4_ioctl+0x1b95/0x5410 fs/ext4/ioctl.c:1606
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
sb_internal --> &sb->s_type->i_mutex_key#8 --> &sbi->s_writepages_rwsem

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&sbi->s_writepages_rwsem);
lock(&sb->s_type->i_mutex_key#8);
lock(&sbi->s_writepages_rwsem);
lock(sb_internal);

*** DEADLOCK ***

3 locks held by syz-executor.5/29299:
#0: ffff88814afb8460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437
#1: ffff88804626ac20 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#1: ffff88804626ac20 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1387 [inline]
#1: ffff88804626ac20 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_ioctl+0x1b8d/0x5410 fs/ext4/ioctl.c:1606
#2: ffff88814afbabd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x212/0x1220 fs/ext4/migrate.c:437

stack backtrace:
CPU: 0 PID: 29299 Comm: syz-executor.5 Not tainted 6.0.0-rc6-syzkaller-00009-g60891ec99e14 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain+0x1873/0x6c00 kernel/locking/lockdep.c:3829
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5053
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
percpu_down_read+0x44/0x190 include/linux/percpu-rwsem.h:51
__sb_start_write include/linux/fs.h:1826 [inline]
sb_start_intwrite include/linux/fs.h:1948 [inline]
ext4_evict_inode+0x4b7/0x1010 fs/ext4/inode.c:240
evict+0x2a4/0x620 fs/inode.c:665
ext4_ext_migrate+0xf3a/0x1220 fs/ext4/migrate.c:587
__ext4_ioctl fs/ext4/ioctl.c:1388 [inline]
ext4_ioctl+0x1b95/0x5410 fs/ext4/ioctl.c:1606
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f0701689409
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0702713168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f070179c050 RCX: 00007f0701689409
RDX: 0000000000000000 RSI: 0000000000006609 RDI: 0000000000000003
RBP: 00007f07016e4367 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc01036e8f R14: 00007f0702713300 R15: 0000000000022000
</TASK>

---
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Next message: Martin Tůma: "Re: [PATCH v2 2/3] Added Xilinx XDMA IP core driver"
Previous message: yassine . oudjana: "Re: [PATCH 1/4] dt-bindings: pinctrl: Combine MediaTek MT67xx pinctrl binding docs"
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