cgroup: fork rejected by pids controller in /syz7
======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc8-next-20221208 #1 Not tainted
------------------------------------------------------
syz-executor.4/18726 is trying to acquire lock:
ffff888010934170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x162/0x310
but task is already holding lock:
ffff888010932b90 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_change_inode_journal_flag+0x17f/0x550
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&sbi->s_writepages_rwsem){++++}-{0:0}:
percpu_down_write+0x51/0x350
ext4_ind_migrate+0x23b/0x840
ext4_fileattr_set+0x1522/0x19f0
vfs_fileattr_set+0x780/0xb90
do_vfs_ioctl+0xa6c/0x1af0
__x64_sys_ioctl+0x110/0x210
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
-> #2 (&sb->s_type->i_mutex_key#6){++++}-{3:3}:
down_read+0x9c/0x450
ext4_bmap+0x52/0x470
bmap+0xb0/0x130
jbd2_journal_bmap+0xac/0x190
jbd2_journal_flush+0x857/0xc10
__ext4_ioctl+0x9c5/0x4540
__x64_sys_ioctl+0x19e/0x210
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
-> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
mutex_lock_io_nested+0x14c/0x1330
jbd2_journal_flush+0x19e/0xc10
__ext4_ioctl+0x9c5/0x4540
__x64_sys_ioctl+0x19e/0x210
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
-> #0 (&journal->j_barrier){+.+.}-{3:3}:
__lock_acquire+0x2a02/0x5e70
lock_acquire+0x1a6/0x530
__mutex_lock+0x136/0x14e0
jbd2_journal_lock_updates+0x162/0x310
ext4_change_inode_journal_flag+0x187/0x550
ext4_fileattr_set+0x14fb/0x19f0
vfs_fileattr_set+0x780/0xb90
do_vfs_ioctl+0xa6c/0x1af0
__x64_sys_ioctl+0x110/0x210
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
other info that might help us debug this:
Chain exists of:
&journal->j_barrier --> &sb->s_type->i_mutex_key#6 --> &sbi->s_writepages_rwsem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sbi->s_writepages_rwsem);
lock(&sb->s_type->i_mutex_key#6);
lock(&sbi->s_writepages_rwsem);
lock(&journal->j_barrier);
*** DEADLOCK ***
4 locks held by syz-executor.4/18726:
#0: ffff888010930438 (sb_writers#3){.+.+}-{0:0}, at: do_vfs_ioctl+0xa2f/0x1af0
#1: ffff88801e9b0400 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: vfs_fileattr_set+0x14c/0xb90
#2: ffff88801e9b05a0 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_change_inode_journal_flag+0x126/0x550
#3: ffff888010932b90 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_change_inode_journal_flag+0x17f/0x550
stack backtrace:
CPU: 1 PID: 18726 Comm: syz-executor.4 Not tainted 6.1.0-rc8-next-20221208 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x8f/0xb7
check_noncircular+0x263/0x2e0
__lock_acquire+0x2a02/0x5e70
lock_acquire+0x1a6/0x530
__mutex_lock+0x136/0x14e0
jbd2_journal_lock_updates+0x162/0x310
ext4_change_inode_journal_flag+0x187/0x550
ext4_fileattr_set+0x14fb/0x19f0
vfs_fileattr_set+0x780/0xb90
do_vfs_ioctl+0xa6c/0x1af0
__x64_sys_ioctl+0x110/0x210
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f4128deeb19
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4126364188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4128f01f60 RCX: 00007f4128deeb19
RDX: 0000000020000040 RSI: 0000000040086602 RDI: 0000000000000003
RBP: 00007f4128e48f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffced93672f R14: 00007f4126364300 R15: 0000000000022000
</TASK>