[syzbot] possible deadlock in static_key_slow_inc (2)

From: syzbot
Date: Wed Nov 02 2022 - 06:37:47 EST

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Hello,

syzbot found the following issue on:

HEAD commit: a2c65a9d0568 net: dsa: fall back to default tagger if we c..
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=10cfb046880000
kernel config: https://syzkaller.appspot.com/x/.config?x=a66c6c673fb555e8
dashboard link: https://syzkaller.appspot.com/bug?extid=c39682e86c9d84152f93
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=159ad4fc880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=159d8591880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c43fc9428e96/disk-a2c65a9d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ef96432b3e62/vmlinux-a2c65a9d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ee926615bbfc/bzImage-a2c65a9d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c39682e86c9d84152f93@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc2-syzkaller-00201-ga2c65a9d0568 #0 Not tainted
------------------------------------------------------
syz-executor229/3606 is trying to acquire lock:
ffffffff8be35130 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_slow_inc+0xe/0x20 kernel/jump_label.c:158

but task is already holding lock:
ffffffff8bfda0c8 (freezer_mutex){+.+.}-{3:3}, at: freezer_change_state kernel/cgroup/legacy_freezer.c:387 [inline]
ffffffff8bfda0c8 (freezer_mutex){+.+.}-{3:3}, at: freezer_write+0x98/0xa50 kernel/cgroup/legacy_freezer.c:426

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (freezer_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
freezer_attach+0x70/0x1f0 kernel/cgroup/legacy_freezer.c:163
cgroup_migrate_execute+0xbcf/0x1230 kernel/cgroup/cgroup.c:2615
cgroup_attach_task+0x41c/0x870 kernel/cgroup/cgroup.c:2906
__cgroup1_procs_write.constprop.0+0x3be/0x4b0 kernel/cgroup/cgroup-v1.c:523
cgroup_file_write+0x1de/0x770 kernel/cgroup/cgroup.c:4057
kernfs_fop_write_iter+0x3f8/0x610 fs/kernfs/file.c:330
call_write_iter include/linux/fs.h:2191 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x9e9/0xdd0 fs/read_write.c:584
ksys_write+0x127/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (cgroup_threadgroup_rwsem){++++}-{0:0}:
percpu_down_write+0x4f/0x390 kernel/locking/percpu-rwsem.c:227
cgroup_attach_lock kernel/cgroup/cgroup.c:2431 [inline]
cgroup_procs_write_start+0x151/0x630 kernel/cgroup/cgroup.c:2935
__cgroup_procs_write+0xd7/0x650 kernel/cgroup/cgroup.c:5135
cgroup_procs_write+0x22/0x50 kernel/cgroup/cgroup.c:5171
cgroup_file_write+0x1de/0x770 kernel/cgroup/cgroup.c:4057
kernfs_fop_write_iter+0x3f8/0x610 fs/kernfs/file.c:330
call_write_iter include/linux/fs.h:2191 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x9e9/0xdd0 fs/read_write.c:584
ksys_write+0x127/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (cpu_hotplug_lock){++++}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain kernel/locking/lockdep.c:3831 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1df/0x630 kernel/locking/lockdep.c:5633
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
cpus_read_lock+0x3e/0x140 kernel/cpu.c:310
static_key_slow_inc+0xe/0x20 kernel/jump_label.c:158
freezer_apply_state+0x1e1/0x260 kernel/cgroup/legacy_freezer.c:353
freezer_change_state kernel/cgroup/legacy_freezer.c:398 [inline]
freezer_write+0x571/0xa50 kernel/cgroup/legacy_freezer.c:426
cgroup_file_write+0x1de/0x770 kernel/cgroup/cgroup.c:4057
kernfs_fop_write_iter+0x3f8/0x610 fs/kernfs/file.c:330
call_write_iter include/linux/fs.h:2191 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x9e9/0xdd0 fs/read_write.c:584
ksys_write+0x127/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
cpu_hotplug_lock --> cgroup_threadgroup_rwsem --> freezer_mutex

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(freezer_mutex);
lock(cgroup_threadgroup_rwsem);
lock(freezer_mutex);
lock(cpu_hotplug_lock);

*** DEADLOCK ***

4 locks held by syz-executor229/3606:
#0: ffff888079bc2460 (sb_writers#10){.+.+}-{0:0}, at: ksys_write+0x127/0x250 fs/read_write.c:637
#1: ffff88801fa91c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x28c/0x610 fs/kernfs/file.c:321
#2: ffff888145b99a00 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b0/0x610 fs/kernfs/file.c:322
#3: ffffffff8bfda0c8 (freezer_mutex){+.+.}-{3:3}, at: freezer_change_state kernel/cgroup/legacy_freezer.c:387 [inline]
#3: ffffffff8bfda0c8 (freezer_mutex){+.+.}-{3:3}, at: freezer_write+0x98/0xa50 kernel/cgroup/legacy_freezer.c:426

stack backtrace:
CPU: 0 PID: 3606 Comm: syz-executor229 Not tainted 6.1.0-rc2-syzkaller-00201-ga2c65a9d0568 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain kernel/locking/lockdep.c:3831 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1df/0x630 kernel/locking/lockdep.c:5633
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
cpus_read_lock+0x3e/0x140 kernel/cpu.c:310
static_key_slow_inc+0xe/0x20 kernel/jump_label.c:158
freezer_apply_state+0x1e1/0x260 kernel/cgroup/legacy_freezer.c:353
freezer_change_state kernel/cgroup/legacy_freezer.c:398 [inline]
freezer_write+0x571/0xa50 kernel/cgroup/legacy_freezer.c:426
cgroup_file_write+0x1de/0x770 kernel/cgroup/cgroup.c:4057
kernfs_fop_write_iter+0x3f8/0x610 fs/kernfs/file.c:330
call_write_iter include/linux/fs.h:2191 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x9e9/0xdd0 fs/read_write.c:584
ksys_write+0x127/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fe89501f769
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 15 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff9816df18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fe89501f769
RDX: 0000000000000007 RSI: 0000000020000040 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00007fff9816df40 R09: 00007fff9816df40
R10: 00007fff9816df40 R11: 0000000000000246 R12: 00007fff9816df3c
R13: 00007fff9816df50 R14: 00007fff9816df90 R15: 0000000000000000
</TASK>

---
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Next message: Kalle Valo: "Re: [PATCH] ath11k: Fix QCN9074 firmware boot on x86"
Previous message: Parikshit Pareek: "[PATCH v7 2/2] arm64: dts: qcom: add SA8540P ride(Qdrive-3)"
Next in thread: syzbot: "Re: [syzbot] possible deadlock in static_key_slow_inc (2)"
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