syzbot


possible deadlock in ext4_setattr

Status: auto-obsoleted due to no activity on 2023/07/21 04:14
Reported-by: syzbot+7767b83bfe5d565c5cba@syzkaller.appspotmail.com
First crash: 458d, last: 453d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ext4_setattr ext4 C done 7 401d 520d 22/27 fixed on 2023/07/01 16:05
upstream possible deadlock in ext4_setattr (2) ext4 1 16d 12d 0/27 upstream: reported on 2024/06/05 21:04

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.104-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/8716 is trying to acquire lock:
ffff888039a62d70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
ffff888039a62d70 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xdaa/0x1990 fs/ext4/inode.c:5446

but task is already holding lock:
ffff888039a62bd0 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff888039a62bd0 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_write+0x97/0x170 kernel/locking/rwsem.c:1541
       inode_lock include/linux/fs.h:787 [inline]
       ext4_xattr_inode_create fs/ext4/xattr.c:1475 [inline]
       ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1558 [inline]
       ext4_xattr_set_entry+0x33c5/0x3c00 fs/ext4/xattr.c:1686
       ext4_xattr_block_set+0xb10/0x3680 fs/ext4/xattr.c:1992
       ext4_xattr_set_handle+0xdac/0x1560 fs/ext4/xattr.c:2407
       ext4_xattr_set+0x231/0x3d0 fs/ext4/xattr.c:2508
       __vfs_setxattr+0x3e7/0x420 fs/xattr.c:182
       __vfs_setxattr_noperm+0x12a/0x5e0 fs/xattr.c:216
       vfs_setxattr+0x21d/0x420 fs/xattr.c:303
       do_setxattr fs/xattr.c:588 [inline]
       setxattr+0x27e/0x2e0 fs/xattr.c:611
       path_setxattr+0x1bc/0x2a0 fs/xattr.c:630
       __do_sys_setxattr fs/xattr.c:646 [inline]
       __se_sys_setxattr fs/xattr.c:642 [inline]
       __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:642
       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+0x61/0xcb

-> #1 (&ei->xattr_sem){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_write+0x97/0x170 kernel/locking/rwsem.c:1541
       ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
       ext4_convert_inline_data+0x3ab/0x610 fs/ext4/inline.c:2043
       ext4_page_mkwrite+0x1ec/0x1290 fs/ext4/inode.c:6103
       do_page_mkwrite+0x1a9/0x440 mm/memory.c:2883
       wp_page_shared+0x179/0x690 mm/memory.c:3216
       handle_pte_fault mm/memory.c:4612 [inline]
       __handle_mm_fault mm/memory.c:4729 [inline]
       handle_mm_fault+0x2a3d/0x5950 mm/memory.c:4827
       do_user_addr_fault arch/x86/mm/fault.c:1397 [inline]
       handle_page_fault arch/x86/mm/fault.c:1485 [inline]
       exc_page_fault+0x271/0x740 arch/x86/mm/fault.c:1541
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568

-> #0 (mapping.invalidate_lock){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_write+0x97/0x170 kernel/locking/rwsem.c:1541
       filemap_invalidate_lock include/linux/fs.h:832 [inline]
       ext4_setattr+0xdaa/0x1990 fs/ext4/inode.c:5446
       notify_change+0xd4d/0x1000 fs/attr.c:488
       do_truncate+0x21c/0x300 fs/open.c:65
       handle_truncate fs/namei.c:3195 [inline]
       do_open fs/namei.c:3542 [inline]
       path_openat+0x28a0/0x2f20 fs/namei.c:3672
       do_filp_open+0x21c/0x460 fs/namei.c:3699
       do_sys_openat2+0x13b/0x500 fs/open.c:1211
       do_sys_open fs/open.c:1227 [inline]
       __do_sys_creat fs/open.c:1301 [inline]
       __se_sys_creat fs/open.c:1295 [inline]
       __x64_sys_creat+0x11f/0x160 fs/open.c:1295
       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+0x61/0xcb

other info that might help us debug this:

Chain exists of:
  mapping.invalidate_lock --> &ei->xattr_sem --> &ea_inode->i_rwsem#9/1

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ea_inode->i_rwsem#9/1);
                               lock(&ei->xattr_sem);
                               lock(&ea_inode->i_rwsem#9/1);
  lock(mapping.invalidate_lock);

 *** DEADLOCK ***

2 locks held by syz-executor.2/8716:
 #0: ffff8880396c2460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
 #1: ffff888039a62bd0 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff888039a62bd0 (&ea_inode->i_rwsem#9/1){+.+.}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63

stack backtrace:
CPU: 1 PID: 8716 Comm: syz-executor.2 Not tainted 5.15.104-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1646/0x58b0 kernel/locking/lockdep.c:3787
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
 down_write+0x97/0x170 kernel/locking/rwsem.c:1541
 filemap_invalidate_lock include/linux/fs.h:832 [inline]
 ext4_setattr+0xdaa/0x1990 fs/ext4/inode.c:5446
 notify_change+0xd4d/0x1000 fs/attr.c:488
 do_truncate+0x21c/0x300 fs/open.c:65
 handle_truncate fs/namei.c:3195 [inline]
 do_open fs/namei.c:3542 [inline]
 path_openat+0x28a0/0x2f20 fs/namei.c:3672
 do_filp_open+0x21c/0x460 fs/namei.c:3699
 do_sys_openat2+0x13b/0x500 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_creat fs/open.c:1301 [inline]
 __se_sys_creat fs/open.c:1295 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1295
 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+0x61/0xcb
RIP: 0033:0x7f72704850f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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:00007f7266616168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f72705a5050 RCX: 00007f72704850f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000000
RBP: 00007f72704e0b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe414369ff R14: 00007f7266616300 R15: 0000000000022000
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/03/23 04:14 linux-5.15.y 115472395b0a f94b4a29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ext4_setattr
2023/03/22 05:46 linux-5.15.y 8020ae3c051d 8b4eb097 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ext4_setattr
2023/03/21 21:24 linux-5.15.y 8020ae3c051d 8b4eb097 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ext4_setattr
2023/03/20 21:19 linux-5.15.y 8020ae3c051d 7939252e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ext4_setattr
2023/03/20 14:49 linux-5.15.y 8020ae3c051d 7939252e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ext4_setattr
2023/03/18 03:29 linux-5.15.y 8020ae3c051d 7939252e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ext4_setattr
* Struck through repros no longer work on HEAD.