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Subject[syzbot] upstream test error: possible deadlock in __fs_reclaim_acquire
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Hello,

syzbot found the following issue on:

HEAD commit: 007b350a Merge tag 'dlm-5.14' of git://git.kernel.org/pub/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1690caac300000
kernel config: https://syzkaller.appspot.com/x/.config?x=d126a83e6a7982cb
dashboard link: https://syzkaller.appspot.com/bug?extid=c259b724a0f86d1f5459
compiler: Debian clang version 11.0.1-2

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c259b724a0f86d1f5459@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.13.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-fuzzer/8414 is trying to acquire lock:
ffffffff8cfd67c0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x30 mm/page_alloc.c:4222

but task is already holding lock:
ffff8880b9a31088 (lock#2){-.-.}-{2:2}, at: local_lock_acquire+0x7/0x130 include/linux/local_lock_internal.h:41

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (lock#2){-.-.}-{2:2}:
lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
local_lock_acquire+0x23/0x130 include/linux/local_lock_internal.h:42
free_unref_page+0x242/0x550 mm/page_alloc.c:3439
mm_free_pgd kernel/fork.c:636 [inline]
__mmdrop+0xae/0x3f0 kernel/fork.c:687
mmdrop include/linux/sched/mm.h:49 [inline]
finish_task_switch+0x221/0x630 kernel/sched/core.c:4582
context_switch kernel/sched/core.c:4686 [inline]
__schedule+0xb5b/0x1450 kernel/sched/core.c:5940
preempt_schedule_irq+0xe3/0x190 kernel/sched/core.c:6328
irqentry_exit+0x56/0x90 kernel/entry/common.c:427
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
lock_acquire+0x1e7/0x4a0 kernel/locking/lockdep.c:5629
__fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4564
fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4578
might_alloc include/linux/sched/mm.h:198 [inline]
slab_pre_alloc_hook mm/slab.h:485 [inline]
slab_alloc_node mm/slub.c:2891 [inline]
slab_alloc mm/slub.c:2978 [inline]
kmem_cache_alloc+0x3a/0x340 mm/slub.c:2983
getname_flags+0xba/0x640 fs/namei.c:138
user_path_at_empty+0x28/0x50 fs/namei.c:2734
user_path_at include/linux/namei.h:60 [inline]
vfs_statx+0x102/0x3d0 fs/stat.c:203
vfs_fstatat fs/stat.c:225 [inline]
vfs_lstat include/linux/fs.h:3384 [inline]
__do_sys_newlstat fs/stat.c:380 [inline]
__se_sys_newlstat fs/stat.c:374 [inline]
__x64_sys_newlstat+0xd3/0x150 fs/stat.c:374
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+0x44/0xae

-> #0 (fs_reclaim){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3051 [inline]
check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174
validate_chain kernel/locking/lockdep.c:3789 [inline]
__lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015
lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
__fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4564
fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4578
prepare_alloc_pages+0x151/0x5a0 mm/page_alloc.c:5176
__alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5375
stack_depot_save+0x361/0x490 lib/stackdepot.c:303
save_stack+0xf9/0x1f0 mm/page_owner.c:120
__set_page_owner+0x42/0x2f0 mm/page_owner.c:181
prep_new_page mm/page_alloc.c:2445 [inline]
__alloc_pages_bulk+0x9f6/0x10b0 mm/page_alloc.c:5313
alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline]
vm_area_alloc_pages mm/vmalloc.c:2775 [inline]
__vmalloc_area_node mm/vmalloc.c:2845 [inline]
__vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2947
vmalloc_user+0x70/0x80 mm/vmalloc.c:3082
kcov_mmap+0x28/0x130 kernel/kcov.c:465
call_mmap include/linux/fs.h:2119 [inline]
mmap_region+0x10e2/0x1da0 mm/mmap.c:1809
do_mmap+0x930/0x11a0 mm/mmap.c:1585
vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:519
ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1636
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+0x44/0xae

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(lock#2);
lock(fs_reclaim);
lock(lock#2);
lock(fs_reclaim);

*** DEADLOCK ***

2 locks held by syz-fuzzer/8414:
#0: ffff8880187fea28 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff8880187fea28 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:517
#1: ffff8880b9a31088 (lock#2){-.-.}-{2:2}, at: local_lock_acquire+0x7/0x130 include/linux/local_lock_internal.h:41

stack backtrace:
CPU: 0 PID: 8414 Comm: syz-fuzzer Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:96
print_circular_bug+0xb17/0xdc0 kernel/locking/lockdep.c:2009
check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2131
check_prev_add kernel/locking/lockdep.c:3051 [inline]
check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174
validate_chain kernel/locking/lockdep.c:3789 [inline]
__lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015
lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
__fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4564
fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4578
prepare_alloc_pages+0x151/0x5a0 mm/page_alloc.c:5176
__alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5375
stack_depot_save+0x361/0x490 lib/stackdepot.c:303
save_stack+0xf9/0x1f0 mm/page_owner.c:120
__set_page_owner+0x42/0x2f0 mm/page_owner.c:181
prep_new_page mm/page_alloc.c:2445 [inline]
__alloc_pages_bulk+0x9f6/0x10b0 mm/page_alloc.c:5313
alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline]
vm_area_alloc_pages mm/vmalloc.c:2775 [inline]
__vmalloc_area_node mm/vmalloc.c:2845 [inline]
__vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2947
vmalloc_user+0x70/0x80 mm/vmalloc.c:3082
kcov_mmap+0x28/0x130 kernel/kcov.c:465
call_mmap include/linux/fs.h:2119 [inline]
mmap_region+0x10e2/0x1da0 mm/mmap.c:1809
do_mmap+0x930/0x11a0 mm/mmap.c:1585
vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:519
ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1636
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+0x44/0xae
RIP: 0033:0x4af20a
Code: e8 3b 82 fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 4c 8b 54 24 28 4c 8b 44 24 30 4c 8b 4c 24 38 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 40 ff ff ff ff 48 c7 44 24 48
RSP: 002b:000000c0003715d8 EFLAGS: 00000212 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 000000c00001c000 RCX: 00000000004af20a
RDX: 0000000000000003 RSI: 0000000000080000 RDI: 0000000000000000
RBP: 000000c000371638 R08: 0000000000000006 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000212 R12: 00000000007798c5
R13: 00000000000000de R14: 00000000000000dd R15: 0000000000000100
BUG: sleeping function called from invalid context at mm/page_alloc.c:5179
in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 8414, name: syz-fuzzer
INFO: lockdep is turned off.
irq event stamp: 67846
hardirqs last enabled at (67845): [<ffffffff89c89aab>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
hardirqs last enabled at (67845): [<ffffffff89c89aab>] _raw_spin_unlock_irqrestore+0x8b/0x120 kernel/locking/spinlock.c:191
hardirqs last disabled at (67846): [<ffffffff81bee901>] __alloc_pages_bulk+0x801/0x10b0 mm/page_alloc.c:5291
softirqs last enabled at (67050): [<ffffffff814d502b>] invoke_softirq kernel/softirq.c:432 [inline]
softirqs last enabled at (67050): [<ffffffff814d502b>] __irq_exit_rcu+0x21b/0x260 kernel/softirq.c:636
softirqs last disabled at (66829): [<ffffffff814d502b>] invoke_softirq kernel/softirq.c:432 [inline]
softirqs last disabled at (66829): [<ffffffff814d502b>] __irq_exit_rcu+0x21b/0x260 kernel/softirq.c:636
CPU: 0 PID: 8414 Comm: syz-fuzzer Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:96
___might_sleep+0x4e5/0x6b0 kernel/sched/core.c:9153
prepare_alloc_pages+0x1c0/0x5a0 mm/page_alloc.c:5179
__alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5375
stack_depot_save+0x361/0x490 lib/stackdepot.c:303
save_stack+0xf9/0x1f0 mm/page_owner.c:120
__set_page_owner+0x42/0x2f0 mm/page_owner.c:181
prep_new_page mm/page_alloc.c:2445 [inline]
__alloc_pages_bulk+0x9f6/0x10b0 mm/page_alloc.c:5313
alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline]
vm_area_alloc_pages mm/vmalloc.c:2775 [inline]
__vmalloc_area_node mm/vmalloc.c:2845 [inline]
__vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2947
vmalloc_user+0x70/0x80 mm/vmalloc.c:3082
kcov_mmap+0x28/0x130 kernel/kcov.c:465
call_mmap include/linux/fs.h:2119 [inline]
mmap_region+0x10e2/0x1da0 mm/mmap.c:1809
do_mmap+0x930/0x11a0 mm/mmap.c:1585
vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:519
ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1636
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+0x44/0xae
RIP: 0033:0x4af20a
Code: e8 3b 82 fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 4c 8b 54 24 28 4c 8b 44 24 30 4c 8b 4c 24 38 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 40 ff ff ff ff 48 c7 44 24 48
RSP: 002b:000000c0003715d8 EFLAGS: 00000212 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 000000c00001c000 RCX: 00000000004af20a
RDX: 0000000000000003 RSI: 0000000000080000 RDI: 0000000000000000
RBP: 000000c000371638 R08: 0000000000000006 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000212 R12: 00000000007798c5
R13: 00000000000000de R14: 00000000000000dd R15: 0000000000000100
can: request_module (can-proto-0) failed.
can: request_module (can-proto-0) failed.
can: request_module (can-proto-0) failed.


---
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