syzbot


possible deadlock in ext4_writepages

Status: auto-obsoleted due to no activity on 2023/08/23 09:09
Reported-by: syzbot+fd1ac060cdca3c56e759@syzkaller.appspotmail.com
First crash: 369d, last: 368d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ext4_writepages ext4 1 631d 627d 0/26 auto-obsoleted due to no activity on 2022/12/11 07:00

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.110-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/10143 is trying to acquire lock:
ffff88801fe10bd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2687

but task is already holding lock:
ffff8880712edf48 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
ffff8880712edf48 (mapping.invalidate_lock){++++}-{3:3}, at: swap_inode_boot_loader fs/ext4/ioctl.c:152 [inline]
ffff8880712edf48 (mapping.invalidate_lock){++++}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1055 [inline]
ffff8880712edf48 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_ioctl+0x39c4/0x5b70 fs/ext4/ioctl.c:1278

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (mapping.invalidate_lock){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_read+0x3b/0x50 kernel/locking/rwsem.c:1488
       filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
       ext4_page_mkwrite+0x1df/0x1290 fs/ext4/inode.c:6101
       do_page_mkwrite+0x1a9/0x440 mm/memory.c:2883
       wp_page_shared+0x179/0x690 mm/memory.c:3216
       handle_pte_fault mm/memory.c:4626 [inline]
       __handle_mm_fault mm/memory.c:4743 [inline]
       handle_mm_fault+0x2a3d/0x5950 mm/memory.c:4841
       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

-> #5 (sb_pagefaults){.+.+}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       percpu_down_read+0x46/0x1b0 include/linux/percpu-rwsem.h:51
       __sb_start_write include/linux/fs.h:1742 [inline]
       sb_start_pagefault include/linux/fs.h:1841 [inline]
       ext4_page_mkwrite+0x1b5/0x1290 fs/ext4/inode.c:6098
       do_page_mkwrite+0x1a9/0x440 mm/memory.c:2883
       wp_page_shared+0x179/0x690 mm/memory.c:3216
       handle_pte_fault mm/memory.c:4626 [inline]
       __handle_mm_fault mm/memory.c:4743 [inline]
       handle_mm_fault+0x2a3d/0x5950 mm/memory.c:4841
       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

-> #4 (&mm->mmap_lock#2){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_write+0x97/0x170 kernel/locking/rwsem.c:1541
       mmap_write_lock include/linux/mmap_lock.h:71 [inline]
       mpol_rebind_mm+0x34/0x2b0 mm/mempolicy.c:381
       cpuset_attach+0x393/0x540 kernel/cgroup/cpuset.c:2289
       cgroup_migrate_execute+0x7fb/0x10e0 kernel/cgroup/cgroup.c:2559
       cgroup_attach_task+0x58a/0x840 kernel/cgroup/cgroup.c:2854
       __cgroup1_procs_write+0x2ec/0x460 kernel/cgroup/cgroup-v1.c:528
       cgroup_file_write+0x2ac/0x670 kernel/cgroup/cgroup.c:3932
       kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296
       call_write_iter include/linux/fs.h:2103 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0xacf/0xe50 fs/read_write.c:594
       ksys_write+0x1a2/0x2c0 fs/read_write.c:647
       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

-> #3 (&cpuset_rwsem){++++}-{0:0}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       cpuset_read_lock+0x40/0x150 kernel/cgroup/cpuset.c:356
       __sched_setscheduler+0x626/0x1df0 kernel/sched/core.c:7409
       _sched_setscheduler kernel/sched/core.c:7586 [inline]
       sched_setscheduler_nocheck+0x187/0x2d0 kernel/sched/core.c:7633
       __kthread_create_on_node+0x31b/0x3f0 kernel/kthread.c:413
       kthread_create_on_node+0xda/0x120 kernel/kthread.c:453
       cryptomgr_schedule_test crypto/algboss.c:219 [inline]
       cryptomgr_notify+0x125/0xc70 crypto/algboss.c:240
       notifier_call_chain kernel/notifier.c:83 [inline]
       blocking_notifier_call_chain+0x104/0x1b0 kernel/notifier.c:318
       crypto_probing_notify+0x21/0x70 crypto/api.c:251
       crypto_wait_for_test+0x3e/0xd0 crypto/algapi.c:396
       crypto_register_alg+0x25b/0x330 crypto/algapi.c:429
       do_one_initcall+0x22b/0x7a0 init/main.c:1306
       do_initcall_level+0x157/0x207 init/main.c:1379
       do_initcalls+0x49/0x86 init/main.c:1395
       kernel_init_freeable+0x43c/0x5c5 init/main.c:1619
       kernel_init+0x19/0x290 init/main.c:1510
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

-> #2 ((crypto_chain).rwsem){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_read+0x3b/0x50 kernel/locking/rwsem.c:1488
       blocking_notifier_call_chain+0x5e/0x1b0 kernel/notifier.c:317
       crypto_probing_notify crypto/api.c:251 [inline]
       crypto_alg_mod_lookup+0x4e6/0x710 crypto/api.c:281
       crypto_find_alg crypto/api.c:490 [inline]
       crypto_alloc_tfm_node+0x12c/0x350 crypto/api.c:527
       cryptd_alloc_skcipher+0xde/0x1f0 crypto/cryptd.c:916
       simd_skcipher_init+0x63/0x130 crypto/simd.c:122
       crypto_create_tfm_node+0x105/0x360 crypto/api.c:457
       crypto_alloc_tfm_node+0x15d/0x350 crypto/api.c:533
       fscrypt_allocate_skcipher fs/crypto/keysetup.c:84 [inline]
       fscrypt_prepare_key+0x89/0x360 fs/crypto/keysetup.c:135
       fscrypt_set_per_file_enc_key fs/crypto/keysetup.c:160 [inline]
       fscrypt_setup_v2_file_key fs/crypto/keysetup.c:349 [inline]
       setup_file_encryption_key fs/crypto/keysetup.c:474 [inline]
       fscrypt_setup_encryption_info+0xcf4/0x13a0 fs/crypto/keysetup.c:553
       fscrypt_prepare_new_inode+0x208/0x2f0 fs/crypto/keysetup.c:698
       __ext4_new_inode+0x86b/0x4390 fs/ext4/ialloc.c:988
       ext4_create+0x275/0x550 fs/ext4/namei.c:2808
       lookup_open fs/namei.c:3392 [inline]
       open_last_lookups fs/namei.c:3462 [inline]
       path_openat+0x12f6/0x2f20 fs/namei.c:3669
       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_open fs/open.c:1235 [inline]
       __se_sys_open fs/open.c:1231 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1231
       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 (&mk->mk_sem){.+.+}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
       down_read+0x3b/0x50 kernel/locking/rwsem.c:1488
       setup_file_encryption_key fs/crypto/keysetup.c:456 [inline]
       fscrypt_setup_encryption_info+0x5b6/0x13a0 fs/crypto/keysetup.c:553
       fscrypt_prepare_new_inode+0x208/0x2f0 fs/crypto/keysetup.c:698
       __ext4_new_inode+0x86b/0x4390 fs/ext4/ialloc.c:988
       ext4_ext_migrate+0x679/0x12f0 fs/ext4/migrate.c:456
       ext4_ioctl_setflags fs/ext4/ioctl.c:455 [inline]
       ext4_fileattr_set+0xf80/0x17d0 fs/ext4/ioctl.c:763
       vfs_fileattr_set+0x8f3/0xd30 fs/ioctl.c:700
       ioctl_setflags fs/ioctl.c:732 [inline]
       do_vfs_ioctl+0x1d85/0x2b70 fs/ioctl.c:843
       __do_sys_ioctl fs/ioctl.c:872 [inline]
       __se_sys_ioctl+0x81/0x160 fs/ioctl.c:860
       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

-> #0 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       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
       percpu_down_read+0x46/0x1b0 include/linux/percpu-rwsem.h:51
       ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2687
       do_writepages+0x481/0x730 mm/page-writeback.c:2364
       filemap_fdatawrite_wbc+0x1d6/0x230 mm/filemap.c:400
       __filemap_fdatawrite_range mm/filemap.c:433 [inline]
       filemap_write_and_wait_range+0x19e/0x280 mm/filemap.c:704
       filemap_write_and_wait include/linux/fs.h:2823 [inline]
       swap_inode_boot_loader fs/ext4/ioctl.c:153 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1055 [inline]
       ext4_ioctl+0x39ff/0x5b70 fs/ext4/ioctl.c:1278
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       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:
  &sbi->s_writepages_rwsem --> sb_pagefaults --> mapping.invalidate_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(mapping.invalidate_lock);
                               lock(sb_pagefaults);
                               lock(mapping.invalidate_lock);
  lock(&sbi->s_writepages_rwsem);

 *** DEADLOCK ***

4 locks held by syz-executor.3/10143:
 #0: ffff88801fe12460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:421
 #1: ffff8880712edda8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff8880712edda8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: lock_two_nondirectories+0xde/0x130 fs/inode.c:1041
 #2: ffff8880850067a0 (&sb->s_type->i_mutex_key#9/4){+.+.}-{3:3}, at: swap_inode_boot_loader fs/ext4/ioctl.c:135 [inline]
 #2: ffff8880850067a0 (&sb->s_type->i_mutex_key#9/4){+.+.}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1055 [inline]
 #2: ffff8880850067a0 (&sb->s_type->i_mutex_key#9/4){+.+.}-{3:3}, at: ext4_ioctl+0x1fff/0x5b70 fs/ext4/ioctl.c:1278
 #3: ffff8880712edf48 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #3: ffff8880712edf48 (mapping.invalidate_lock){++++}-{3:3}, at: swap_inode_boot_loader fs/ext4/ioctl.c:152 [inline]
 #3: ffff8880712edf48 (mapping.invalidate_lock){++++}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1055 [inline]
 #3: ffff8880712edf48 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_ioctl+0x39c4/0x5b70 fs/ext4/ioctl.c:1278

stack backtrace:
CPU: 0 PID: 10143 Comm: syz-executor.3 Not tainted 5.15.110-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
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
 percpu_down_read+0x46/0x1b0 include/linux/percpu-rwsem.h:51
 ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2687
 do_writepages+0x481/0x730 mm/page-writeback.c:2364
 filemap_fdatawrite_wbc+0x1d6/0x230 mm/filemap.c:400
 __filemap_fdatawrite_range mm/filemap.c:433 [inline]
 filemap_write_and_wait_range+0x19e/0x280 mm/filemap.c:704
 filemap_write_and_wait include/linux/fs.h:2823 [inline]
 swap_inode_boot_loader fs/ext4/ioctl.c:153 [inline]
 __ext4_ioctl fs/ext4/ioctl.c:1055 [inline]
 ext4_ioctl+0x39ff/0x5b70 fs/ext4/ioctl.c:1278
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
 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: 0033:0x7f9145936169
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:00007f913bb66168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9145a56120 RCX: 00007f9145936169
RDX: 0000000000000000 RSI: 0000000000006611 RDI: 0000000000000004
RBP: 00007f9145991ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc221dd78f R14: 00007f913bb66300 R15: 0000000000022000
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/05/04 04:02 linux-5.15.y 8a7f2a5c5aa1 b5918830 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ext4_writepages
2023/05/02 17:20 linux-5.15.y 8a7f2a5c5aa1 52d40fd2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ext4_writepages
* Struck through repros no longer work on HEAD.