Message-ID: <6863c629.a70a0220.3b7e22.19d9.GAE@google.com>
Date: Tue, 01 Jul 2025 04:27:37 -0700
From: syzbot <syzbot+32ed484f0f32dcc41c43@...kaller.appspotmail.com>
To: adilger.kernel@...ger.ca, linux-ext4@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com, tytso@....edu
Subject: [syzbot] [ext4?] possible deadlock in ext4_inline_data_truncate (4)

Hello,

syzbot found the following issue on:

HEAD commit:    2aeda9592360 Add linux-next specific files for 20250627
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=157b608c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7f5c1d958b70bf47
dashboard link: https://syzkaller.appspot.com/bug?extid=32ed484f0f32dcc41c43
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d532560074a3/disk-2aeda959.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/483001f76864/vmlinux-2aeda959.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8f233cdc1c77/bzImage-2aeda959.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+32ed484f0f32dcc41c43@...kaller.appspotmail.com

EXT4-fs: Ignoring removed orlov option
EXT4-fs: Ignoring removed nomblk_io_submit option
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc3-next-20250627-syzkaller #0 Not tainted
------------------------------------------------------
syz.0.4438/18397 is trying to acquire lock:
ffff8880565ef388 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline]
ffff8880565ef388 (&ei->xattr_sem){++++}-{4:4}, at: ext4_inline_data_truncate+0x1a9/0xad0 fs/ext4/inline.c:1872

but task is already holding lock:
ffff888067462618 (sb_internal){++++}-{0:0}, at: percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
ffff888067462618 (sb_internal){++++}-{0:0}, at: __sb_start_write include/linux/fs.h:1798 [inline]
ffff888067462618 (sb_internal){++++}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1981 [inline]
ffff888067462618 (sb_internal){++++}-{0:0}, at: ext4_evict_inode+0x2d6/0xee0 fs/ext4/inode.c:215

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (sb_internal){++++}-{0:0}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       percpu_down_write+0x54/0x330 kernel/locking/percpu-rwsem.c:232
       sb_wait_write fs/super.c:1900 [inline]
       freeze_super+0x8b7/0x1130 fs/super.c:2183
       fs_bdev_freeze+0x1a3/0x310 fs/super.c:1529
       bdev_freeze+0xd8/0x220 block/bdev.c:298
       ext4_force_shutdown+0x322/0x560 fs/ext4/ioctl.c:822
       ext4_ioctl_shutdown fs/ext4/ioctl.c:857 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1587 [inline]
       ext4_ioctl+0x1d39/0x3510 fs/ext4/ioctl.c:1626
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:907 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (sb_pagefaults){++++}-{0:0}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       percpu_down_read_internal+0x48/0x1c0 include/linux/percpu-rwsem.h:53
       percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
       __sb_start_write include/linux/fs.h:1798 [inline]
       sb_start_pagefault include/linux/fs.h:1963 [inline]
       ext4_page_mkwrite+0x1e3/0x1110 fs/ext4/inode.c:6575
       do_page_mkwrite+0x14a/0x310 mm/memory.c:3374
       do_shared_fault mm/memory.c:5662 [inline]
       do_fault mm/memory.c:5724 [inline]
       do_pte_missing mm/memory.c:4247 [inline]
       handle_pte_fault mm/memory.c:6065 [inline]
       __handle_mm_fault+0x1916/0x5440 mm/memory.c:6208
       handle_mm_fault+0x40a/0x8e0 mm/memory.c:6377
       do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387
       handle_page_fault arch/x86/mm/fault.c:1476 [inline]
       exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

-> #3 (&mm->mmap_lock){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __might_fault+0xcc/0x130 mm/memory.c:6967
       _inline_copy_to_user include/linux/uaccess.h:192 [inline]
       _copy_to_user+0x2c/0xb0 lib/usercopy.c:26
       copy_to_user include/linux/uaccess.h:225 [inline]
       fiemap_fill_next_extent+0x1c0/0x390 fs/ioctl.c:145
       ocfs2_fiemap+0x888/0xc90 fs/ocfs2/extent_map.c:806
       ioctl_fiemap fs/ioctl.c:220 [inline]
       do_vfs_ioctl+0x16d0/0x1990 fs/ioctl.c:841
       __do_sys_ioctl fs/ioctl.c:905 [inline]
       __se_sys_ioctl+0x82/0x170 fs/ioctl.c:893
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&ocfs2_quota_ip_alloc_sem_key){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
       ocfs2_create_local_dquot+0x19d/0x1a40 fs/ocfs2/quota_local.c:1227
       ocfs2_acquire_dquot+0x80f/0xb30 fs/ocfs2/quota_global.c:883
       dqget+0x7ae/0xf10 fs/quota/dquot.c:977
       ocfs2_setattr+0xd72/0x1b40 fs/ocfs2/file.c:1233
       notify_change+0xb36/0xe40 fs/attr.c:552
       chown_common+0x40c/0x5c0 fs/open.c:790
       do_fchownat+0x161/0x270 fs/open.c:821
       __do_sys_lchown fs/open.c:846 [inline]
       __se_sys_lchown fs/open.c:844 [inline]
       __x64_sys_lchown+0x85/0xa0 fs/open.c:844
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&dquot->dq_lock){+.+.}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
       wait_on_dquot fs/quota/dquot.c:354 [inline]
       dqget+0x72a/0xf10 fs/quota/dquot.c:972
       dquot_transfer+0x2f8/0x6d0 fs/quota/dquot.c:2140
       ext4_setattr+0x865/0x1bc0 fs/ext4/inode.c:5816
       notify_change+0xb36/0xe40 fs/attr.c:552
       chown_common+0x40c/0x5c0 fs/open.c:790
       do_fchownat+0x161/0x270 fs/open.c:821
       __do_sys_chown fs/open.c:841 [inline]
       __se_sys_chown fs/open.c:839 [inline]
       __x64_sys_chown+0x82/0xa0 fs/open.c:839
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ei->xattr_sem){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
       ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline]
       ext4_inline_data_truncate+0x1a9/0xad0 fs/ext4/inline.c:1872
       ext4_truncate+0x3b5/0x1100 fs/ext4/inode.c:4527
       ext4_evict_inode+0x8cf/0xee0 fs/ext4/inode.c:261
       evict+0x501/0x9c0 fs/inode.c:810
       __dentry_kill+0x209/0x660 fs/dcache.c:669
       dput+0x19f/0x2b0 fs/dcache.c:911
       do_renameat2+0x6de/0xa80 fs/namei.c:5280
       __do_sys_rename fs/namei.c:5325 [inline]
       __se_sys_rename fs/namei.c:5323 [inline]
       __x64_sys_rename+0x82/0x90 fs/namei.c:5323
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &ei->xattr_sem --> sb_pagefaults --> sb_internal

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_internal);
                               lock(sb_pagefaults);
                               lock(sb_internal);
  lock(&ei->xattr_sem);

 *** DEADLOCK ***

5 locks held by syz.0.4438/18397:
 #0: ffff888067462428 (sb_writers#4){++++}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff888067462738 (&type->s_vfs_rename_key#2){+.+.}-{4:4}, at: lock_rename fs/namei.c:3276 [inline]
 #1: ffff888067462738 (&type->s_vfs_rename_key#2){+.+.}-{4:4}, at: do_renameat2+0x364/0xa80 fs/namei.c:5224
 #2: ffff88803ed85060 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
 #2: ffff88803ed85060 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: lock_two_directories+0x1a2/0x220 fs/namei.c:3252
 #3: ffff88803ed83d40 (&type->i_mutex_dir_key#3/5){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
 #3: ffff88803ed83d40 (&type->i_mutex_dir_key#3/5){+.+.}-{4:4}, at: lock_two_directories+0x1cc/0x220 fs/namei.c:3253
 #4: ffff888067462618 (sb_internal){++++}-{0:0}, at: percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
 #4: ffff888067462618 (sb_internal){++++}-{0:0}, at: __sb_start_write include/linux/fs.h:1798 [inline]
 #4: ffff888067462618 (sb_internal){++++}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1981 [inline]
 #4: ffff888067462618 (sb_internal){++++}-{0:0}, at: ext4_evict_inode+0x2d6/0xee0 fs/ext4/inode.c:215

stack backtrace:
CPU: 0 UID: 0 PID: 18397 Comm: syz.0.4438 Not tainted 6.16.0-rc3-next-20250627-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline]
 ext4_inline_data_truncate+0x1a9/0xad0 fs/ext4/inline.c:1872
 ext4_truncate+0x3b5/0x1100 fs/ext4/inode.c:4527
 ext4_evict_inode+0x8cf/0xee0 fs/ext4/inode.c:261
 evict+0x501/0x9c0 fs/inode.c:810
 __dentry_kill+0x209/0x660 fs/dcache.c:669
 dput+0x19f/0x2b0 fs/dcache.c:911
 do_renameat2+0x6de/0xa80 fs/namei.c:5280
 __do_sys_rename fs/namei.c:5325 [inline]
 __se_sys_rename fs/namei.c:5323 [inline]
 __x64_sys_rename+0x82/0x90 fs/namei.c:5323
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f452478e929
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f452556f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007f45249b5fa0 RCX: 00007f452478e929
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000200000000080
RBP: 00007f4524810b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f45249b5fa0 R15: 00007ffed20051f8
 </TASK>


---
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