[syzbot] possible deadlock in perf_event_ctx_lock_nested (2)

From: syzbot
Date: Mon May 17 2021 - 07:17:26 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 88b06399 Merge tag 'for-5.13-rc1-part2-tag' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15552e1bd00000
kernel config: https://syzkaller.appspot.com/x/.config?x=807beec6b4d66bf1
dashboard link: https://syzkaller.appspot.com/bug?extid=4b71bb3365e7d5228913

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4b71bb3365e7d5228913@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
5.13.0-rc1-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/26566 is trying to acquire lock:
ffff88808aa32b58 (&mm->mmap_lock#2){++++}-{3:3}, at: __might_fault+0xa3/0x180 mm/memory.c:5069

but task is already holding lock:
ffff8880b9c3a4b0 (&cpuctx_mutex){+.+.}-{3:3}, at: perf_event_ctx_lock_nested+0x26c/0x480 kernel/events/core.c:1356

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&cpuctx_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:949 [inline]
__mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
perf_event_init_cpu+0x172/0x3e0 kernel/events/core.c:13236
perf_event_init+0x39d/0x408 kernel/events/core.c:13283
start_kernel+0x2b6/0x496 init/main.c:1001
secondary_startup_64_no_verify+0xb0/0xbb

-> #2 (pmus_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:949 [inline]
__mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
perf_event_init_cpu+0xc4/0x3e0 kernel/events/core.c:13230
cpuhp_invoke_callback+0x3b5/0x9a0 kernel/cpu.c:179
cpuhp_invoke_callback_range kernel/cpu.c:654 [inline]
cpuhp_up_callbacks kernel/cpu.c:682 [inline]
_cpu_up+0x3ab/0x6b0 kernel/cpu.c:1301
cpu_up kernel/cpu.c:1336 [inline]
cpu_up+0xfe/0x1a0 kernel/cpu.c:1308
bringup_nonboot_cpus+0xfe/0x130 kernel/cpu.c:1398
smp_init+0x2e/0x145 kernel/smp.c:1090
kernel_init_freeable+0x402/0x6cc init/main.c:1552
kernel_init+0xd/0x1b8 init/main.c:1447
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

-> #1 (cpu_hotplug_lock){++++}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
cpus_read_lock+0x40/0x130 kernel/cpu.c:297
__static_key_slow_dec kernel/jump_label.c:254 [inline]
static_key_slow_dec+0x4f/0xc0 kernel/jump_label.c:270
sw_perf_event_destroy+0x99/0x140 kernel/events/core.c:9544
_free_event+0x2ee/0x1380 kernel/events/core.c:4949
put_event kernel/events/core.c:5043 [inline]
perf_mmap_close+0x572/0xe10 kernel/events/core.c:6088
remove_vma+0xae/0x170 mm/mmap.c:186
remove_vma_list mm/mmap.c:2659 [inline]
__do_munmap+0x74f/0x11a0 mm/mmap.c:2915
do_munmap mm/mmap.c:2923 [inline]
munmap_vma_range mm/mmap.c:604 [inline]
mmap_region+0x85a/0x1730 mm/mmap.c:1756
do_mmap+0xcff/0x11d0 mm/mmap.c:1587
vm_mmap_pgoff+0x1b7/0x290 mm/util.c:519
ksys_mmap_pgoff+0x4a8/0x620 mm/mmap.c:1638
do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (&mm->mmap_lock#2){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:2938 [inline]
check_prevs_add kernel/locking/lockdep.c:3061 [inline]
validate_chain kernel/locking/lockdep.c:3676 [inline]
__lock_acquire+0x2a17/0x5230 kernel/locking/lockdep.c:4902
lock_acquire kernel/locking/lockdep.c:5512 [inline]
lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5477
__might_fault mm/memory.c:5070 [inline]
__might_fault+0x106/0x180 mm/memory.c:5055
_copy_to_user+0x27/0x150 lib/usercopy.c:28
copy_to_user include/linux/uaccess.h:200 [inline]
_perf_ioctl+0x882/0x2650 kernel/events/core.c:5603
perf_ioctl+0x76/0xb0 kernel/events/core.c:5683
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:1069 [inline]
__se_sys_ioctl fs/ioctl.c:1055 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

Chain exists of:
&mm->mmap_lock#2 --> pmus_lock --> &cpuctx_mutex

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&cpuctx_mutex);
lock(pmus_lock);
lock(&cpuctx_mutex);
lock(&mm->mmap_lock#2);

*** DEADLOCK ***

1 lock held by syz-executor.0/26566:
#0: ffff8880b9c3a4b0 (&cpuctx_mutex){+.+.}-{3:3}, at: perf_event_ctx_lock_nested+0x26c/0x480 kernel/events/core.c:1356

stack backtrace:
CPU: 1 PID: 26566 Comm: syz-executor.0 Not tainted 5.13.0-rc1-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+0x141/0x1d7 lib/dump_stack.c:120
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2129
check_prev_add kernel/locking/lockdep.c:2938 [inline]
check_prevs_add kernel/locking/lockdep.c:3061 [inline]
validate_chain kernel/locking/lockdep.c:3676 [inline]
__lock_acquire+0x2a17/0x5230 kernel/locking/lockdep.c:4902
lock_acquire kernel/locking/lockdep.c:5512 [inline]
lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5477
__might_fault mm/memory.c:5070 [inline]
__might_fault+0x106/0x180 mm/memory.c:5055
_copy_to_user+0x27/0x150 lib/usercopy.c:28
copy_to_user include/linux/uaccess.h:200 [inline]
_perf_ioctl+0x882/0x2650 kernel/events/core.c:5603
perf_ioctl+0x76/0xb0 kernel/events/core.c:5683
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:1069 [inline]
__se_sys_ioctl fs/ioctl.c:1055 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665f9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f021b976188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665f9
RDX: 0000000020000000 RSI: 0000000080082407 RDI: 0000000000000003
RBP: 00000000004bfce1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffdd1a9f15f R14: 00007f021b976300 R15: 0000000000022000

---
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Next message: syzbot: "[syzbot] net-next boot error: can't ssh into the instance (4)"
Previous message: Michael Ellerman: "Re: [PATCH] watchdog: Remove MV64x60 watchdog driver"
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