syzbot


possible deadlock in mempool_alloc_noprof

Status: upstream: reported on 2024/06/16 01:04
Subsystems: f2fs
[Documentation on labels]
Reported-by: syzbot+9a18f6f681a8e79a3654@syzkaller.appspotmail.com
First crash: 37d, last: 28d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [f2fs?] possible deadlock in mempool_alloc_noprof 0 (1) 2024/06/16 01:04

Sample crash report:
fscrypt: AES-256-CBC-CTS using implementation "cts-cbc-aes-aesni"
======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0 Not tainted
------------------------------------------------------
syz-executor.3/6842 is trying to acquire lock:
ffffffff8dd3aac0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:334 [inline]
ffffffff8dd3aac0 (fs_reclaim){+.+.}-{0:0}, at: mempool_alloc_noprof+0xd9/0x390 mm/mempool.c:392

but task is already holding lock:
ffff88802be9c3a8 (&sbi->cp_rwsem){++++}-{3:3}, at: f2fs_down_read fs/f2fs/f2fs.h:2154 [inline]
ffff88802be9c3a8 (&sbi->cp_rwsem){++++}-{3:3}, at: f2fs_lock_op fs/f2fs/f2fs.h:2203 [inline]
ffff88802be9c3a8 (&sbi->cp_rwsem){++++}-{3:3}, at: f2fs_mkdir+0x297/0x620 fs/f2fs/namei.c:778

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&sbi->cp_rwsem){++++}-{3:3}:
       down_read+0x9a/0x330 kernel/locking/rwsem.c:1526
       f2fs_down_read fs/f2fs/f2fs.h:2154 [inline]
       f2fs_lock_op fs/f2fs/f2fs.h:2203 [inline]
       f2fs_evict_inode+0x115a/0x1e50 fs/f2fs/inode.c:866
       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
       do_unlinkat+0x613/0x750 fs/namei.c:4414
       __do_sys_unlink fs/namei.c:4455 [inline]
       __se_sys_unlink fs/namei.c:4453 [inline]
       __ia32_sys_unlink+0xc6/0x110 fs/namei.c:4453
       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

-> #1 (sb_internal#4){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1655 [inline]
       sb_start_intwrite include/linux/fs.h:1838 [inline]
       f2fs_evict_inode+0x1844/0x1e50 fs/f2fs/inode.c:853
       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:3801 [inline]
       fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3815
       might_alloc include/linux/sched/mm.h:334 [inline]
       mempool_alloc_noprof+0xd9/0x390 mm/mempool.c:392
       bio_alloc_bioset+0x480/0x8b0 block/bio.c:554
       f2fs_grab_read_bio+0x268/0x7d0 fs/f2fs/data.c:1050
       f2fs_submit_page_read+0xaa/0x1d0 fs/f2fs/data.c:1095
       f2fs_get_read_data_page+0x304/0xaf0 fs/f2fs/data.c:1271
       f2fs_find_data_page+0x13b/0x720 fs/f2fs/data.c:1293
       find_in_level fs/f2fs/dir.c:323 [inline]
       __f2fs_find_entry+0x3fd/0xc80 fs/f2fs/dir.c:388
       f2fs_do_add_link+0x109/0x290 fs/f2fs/dir.c:818
       f2fs_add_link fs/f2fs/f2fs.h:3586 [inline]
       f2fs_mkdir+0x37b/0x620 fs/f2fs/namei.c:779
       vfs_mkdir+0x57d/0x860 fs/namei.c:4131
       do_mkdirat+0x301/0x3a0 fs/namei.c:4154
       __do_sys_mkdirat fs/namei.c:4169 [inline]
       __se_sys_mkdirat fs/namei.c:4167 [inline]
       __ia32_sys_mkdirat+0x84/0xb0 fs/namei.c:4167
       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:

Chain exists of:
  fs_reclaim --> sb_internal#4 --> &sbi->cp_rwsem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(&sbi->cp_rwsem);
                               lock(sb_internal#4);
                               lock(&sbi->cp_rwsem);
  lock(fs_reclaim);

 *** DEADLOCK ***

3 locks held by syz-executor.3/6842:
 #0: ffff888000328420 (sb_writers#15){.+.+}-{0:0}, at: filename_create+0x10d/0x530 fs/namei.c:3893
 #1: ffff88804c163630 (&type->i_mutex_dir_key#11/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:826 [inline]
 #1: ffff88804c163630 (&type->i_mutex_dir_key#11/1){+.+.}-{3:3}, at: filename_create+0x1c2/0x530 fs/namei.c:3900
 #2: ffff88802be9c3a8 (&sbi->cp_rwsem){++++}-{3:3}, at: f2fs_down_read fs/f2fs/f2fs.h:2154 [inline]
 #2: ffff88802be9c3a8 (&sbi->cp_rwsem){++++}-{3:3}, at: f2fs_lock_op fs/f2fs/f2fs.h:2203 [inline]
 #2: ffff88802be9c3a8 (&sbi->cp_rwsem){++++}-{3:3}, at: f2fs_mkdir+0x297/0x620 fs/f2fs/namei.c:778

stack backtrace:
CPU: 0 PID: 6842 Comm: syz-executor.3 Not tainted 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #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:3801 [inline]
 fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3815
 might_alloc include/linux/sched/mm.h:334 [inline]
 mempool_alloc_noprof+0xd9/0x390 mm/mempool.c:392
 bio_alloc_bioset+0x480/0x8b0 block/bio.c:554
 f2fs_grab_read_bio+0x268/0x7d0 fs/f2fs/data.c:1050
 f2fs_submit_page_read+0xaa/0x1d0 fs/f2fs/data.c:1095
 f2fs_get_read_data_page+0x304/0xaf0 fs/f2fs/data.c:1271
 f2fs_find_data_page+0x13b/0x720 fs/f2fs/data.c:1293
 find_in_level fs/f2fs/dir.c:323 [inline]
 __f2fs_find_entry+0x3fd/0xc80 fs/f2fs/dir.c:388
 f2fs_do_add_link+0x109/0x290 fs/f2fs/dir.c:818
 f2fs_add_link fs/f2fs/f2fs.h:3586 [inline]
 f2fs_mkdir+0x37b/0x620 fs/f2fs/namei.c:779
 vfs_mkdir+0x57d/0x860 fs/namei.c:4131
 do_mkdirat+0x301/0x3a0 fs/namei.c:4154
 __do_sys_mkdirat fs/namei.c:4169 [inline]
 __se_sys_mkdirat fs/namei.c:4167 [inline]
 __ia32_sys_mkdirat+0x84/0xb0 fs/namei.c:4167
 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: 0023:0xf727d579
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:00000000f5e4e5ac EFLAGS: 00000292 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000020000080
RDX: 0000000000000000 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

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/20 10:43 upstream 2ccbdf43d5e7 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in mempool_alloc_noprof
2024/06/17 03:28 upstream 2ccbdf43d5e7 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in mempool_alloc_noprof
2024/06/15 17:13 upstream 2ccbdf43d5e7 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in mempool_alloc_noprof
2024/06/12 00:54 upstream 2ef5971ff345 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in mempool_alloc_noprof
* Struck through repros no longer work on HEAD.