syzbot

======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc5-syzkaller-00018-g55027e689933 #0 Not tainted
------------------------------------------------------
syz.1.915/8243 is trying to acquire lock:
ffffffff8dd3a040 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:334 [inline]
ffffffff8dd3a040 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:3891 [inline]
ffffffff8dd3a040 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:3981 [inline]
ffffffff8dd3a040 (fs_reclaim){+.+.}-{0:0}, at: __do_kmalloc_node mm/slub.c:4121 [inline]
ffffffff8dd3a040 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_node_noprof+0xbb/0x450 mm/slub.c:4129

but task is already holding lock:
ffff888000fb14c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
ffff888000fb14c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5822 [inline]
ffff888000fb14c8 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x4cf/0x890 fs/ext4/inode.c:5903

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&ei->xattr_sem){++++}-{3:3}:
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
       ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
       ext4_xattr_set_handle+0x156/0x16d0 fs/ext4/xattr.c:2367
       ext4_set_context+0x400/0x5a0 fs/ext4/crypto.c:202
       set_encryption_policy+0x2cc/0x470 fs/crypto/policy.c:500
       fscrypt_ioctl_set_policy+0x4a2/0x500 fs/crypto/policy.c:553
       __ext4_ioctl+0x2f8f/0x4740 fs/ext4/ioctl.c:1519
       ext4_ioctl fs/ext4/ioctl.c:1626 [inline]
       ext4_compat_ioctl+0xca/0x460 fs/ext4/ioctl.c:1702
       __do_compat_sys_ioctl+0x2c3/0x330 fs/ioctl.c:1007
       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

-> #2 (jbd2_handle){++++}-{0:0}:
       start_this_handle+0x1101/0x15e0 fs/jbd2/transaction.c:463
       jbd2__journal_start+0x394/0x6a0 fs/jbd2/transaction.c:520
       __ext4_journal_start_sb+0x358/0x660 fs/ext4/ext4_jbd2.c:112
       ext4_sample_last_mounted fs/ext4/file.c:837 [inline]
       ext4_file_open+0x636/0xc90 fs/ext4/file.c:865
       do_dentry_open+0x910/0x1930 fs/open.c:955
       do_open fs/namei.c:3650 [inline]
       path_openat+0x1e3a/0x29f0 fs/namei.c:3807
       do_filp_open+0x1dc/0x430 fs/namei.c:3834
       do_sys_openat2+0x17a/0x1e0 fs/open.c:1405
       do_sys_open fs/open.c:1420 [inline]
       __do_sys_openat fs/open.c:1436 [inline]
       __se_sys_openat fs/open.c:1431 [inline]
       __x64_sys_openat+0x175/0x210 fs/open.c:1431
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (sb_internal){.+.+}-{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]
       ext4_evict_inode+0xd7b/0x17d0 fs/ext4/inode.c:212
       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]
       slab_pre_alloc_hook mm/slub.c:3891 [inline]
       slab_alloc_node mm/slub.c:3981 [inline]
       __do_kmalloc_node mm/slub.c:4121 [inline]
       __kmalloc_node_noprof+0xbb/0x450 mm/slub.c:4129
       kmalloc_node_noprof include/linux/slab.h:681 [inline]
       kvmalloc_node_noprof+0x9d/0x1a0 mm/util.c:634
       ext4_xattr_inode_cache_find fs/ext4/xattr.c:1535 [inline]
       ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1581 [inline]
       ext4_xattr_inode_lookup_create+0x4e8/0x1910 fs/ext4/xattr.c:1568
       ext4_xattr_block_set+0x77a/0x3090 fs/ext4/xattr.c:1910
       ext4_xattr_move_to_block fs/ext4/xattr.c:2663 [inline]
       ext4_xattr_make_inode_space fs/ext4/xattr.c:2738 [inline]
       ext4_expand_extra_isize_ea+0xf57/0x1990 fs/ext4/xattr.c:2830
       __ext4_expand_extra_isize+0x322/0x450 fs/ext4/inode.c:5782
       ext4_try_to_expand_extra_isize fs/ext4/inode.c:5825 [inline]
       __ext4_mark_inode_dirty+0x55a/0x890 fs/ext4/inode.c:5903
       ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:5935
       __mark_inode_dirty+0x1f0/0xe70 fs/fs-writeback.c:2486
       generic_update_time+0xcf/0xf0 fs/inode.c:1907
       inode_update_time fs/inode.c:1920 [inline]
       touch_atime+0x4ee/0x5d0 fs/inode.c:1992
       file_accessed include/linux/fs.h:2458 [inline]
       filemap_read+0xb2b/0xd10 mm/filemap.c:2693
       generic_file_read_iter+0x350/0x460 mm/filemap.c:2806
       ext4_file_read_iter+0x1dc/0x6c0 fs/ext4/file.c:147
       __kernel_read+0x3ec/0xb50 fs/read_write.c:434
       kernel_read+0x55/0x70 fs/read_write.c:452
       prepare_binprm fs/exec.c:1732 [inline]
       search_binary_handler fs/exec.c:1781 [inline]
       exec_binprm fs/exec.c:1839 [inline]
       bprm_execve fs/exec.c:1891 [inline]
       bprm_execve+0x61e/0x19b0 fs/exec.c:1867
       do_execveat_common.isra.0+0x5cb/0x750 fs/exec.c:1998
       compat_do_execve fs/exec.c:2099 [inline]
       __do_compat_sys_execve fs/exec.c:2167 [inline]
       __se_compat_sys_execve fs/exec.c:2163 [inline]
       __ia32_compat_sys_execve+0x90/0xc0 fs/exec.c:2163
       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 --> jbd2_handle --> &ei->xattr_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->xattr_sem);
                               lock(jbd2_handle);
                               lock(&ei->xattr_sem);
  lock(fs_reclaim);

 *** DEADLOCK ***

3 locks held by syz.1.915/8243:
 #0: ffff8880265148c8 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: prepare_bprm_creds fs/exec.c:1513 [inline]
 #0: ffff8880265148c8 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: bprm_execve+0xa5/0x19b0 fs/exec.c:1871
 #1: ffff888028d7c420 (sb_writers#4){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2458 [inline]
 #1: ffff888028d7c420 (sb_writers#4){.+.+}-{0:0}, at: filemap_read+0xb2b/0xd10 mm/filemap.c:2693
 #2: ffff888000fb14c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
 #2: ffff888000fb14c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5822 [inline]
 #2: ffff888000fb14c8 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x4cf/0x890 fs/ext4/inode.c:5903

stack backtrace:
CPU: 2 PID: 8243 Comm: syz.1.915 Not tainted 6.10.0-rc5-syzkaller-00018-g55027e689933 #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: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]
 slab_pre_alloc_hook mm/slub.c:3891 [inline]
 slab_alloc_node mm/slub.c:3981 [inline]
 __do_kmalloc_node mm/slub.c:4121 [inline]
 __kmalloc_node_noprof+0xbb/0x450 mm/slub.c:4129
 kmalloc_node_noprof include/linux/slab.h:681 [inline]
 kvmalloc_node_noprof+0x9d/0x1a0 mm/util.c:634
 ext4_xattr_inode_cache_find fs/ext4/xattr.c:1535 [inline]
 ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1581 [inline]
 ext4_xattr_inode_lookup_create+0x4e8/0x1910 fs/ext4/xattr.c:1568
 ext4_xattr_block_set+0x77a/0x3090 fs/ext4/xattr.c:1910
 ext4_xattr_move_to_block fs/ext4/xattr.c:2663 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2738 [inline]
 ext4_expand_extra_isize_ea+0xf57/0x1990 fs/ext4/xattr.c:2830
 __ext4_expand_extra_isize+0x322/0x450 fs/ext4/inode.c:5782
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5825 [inline]
 __ext4_mark_inode_dirty+0x55a/0x890 fs/ext4/inode.c:5903
 ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:5935
 __mark_inode_dirty+0x1f0/0xe70 fs/fs-writeback.c:2486
 generic_update_time+0xcf/0xf0 fs/inode.c:1907
 inode_update_time fs/inode.c:1920 [inline]
 touch_atime+0x4ee/0x5d0 fs/inode.c:1992
 file_accessed include/linux/fs.h:2458 [inline]
 filemap_read+0xb2b/0xd10 mm/filemap.c:2693
 generic_file_read_iter+0x350/0x460 mm/filemap.c:2806
 ext4_file_read_iter+0x1dc/0x6c0 fs/ext4/file.c:147
 __kernel_read+0x3ec/0xb50 fs/read_write.c:434
 kernel_read+0x55/0x70 fs/read_write.c:452
 prepare_binprm fs/exec.c:1732 [inline]
 search_binary_handler fs/exec.c:1781 [inline]
 exec_binprm fs/exec.c:1839 [inline]
 bprm_execve fs/exec.c:1891 [inline]
 bprm_execve+0x61e/0x19b0 fs/exec.c:1867
 do_execveat_common.isra.0+0x5cb/0x750 fs/exec.c:1998
 compat_do_execve fs/exec.c:2099 [inline]
 __do_compat_sys_execve fs/exec.c:2167 [inline]
 __se_compat_sys_execve fs/exec.c:2163 [inline]
 __ia32_compat_sys_execve+0x90/0xc0 fs/exec.c:2163
 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: 0023:0xf74a1579
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:00000000f5db957c EFLAGS: 00000292 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 0000000000000000
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