Subject: [syzbot] WARNING in ctx_sched_in

From: syzbot <[email-masked]>
Date: Thu, 15 Apr 2021 21:35:15 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    79c338ab riscv: keep interrupts disabled for BREAKPOINT ex..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes
console output: https://syzkaller.appspot.com/x/log.txt?x=10fb93f9d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f8af20e245283c9a
dashboard link: https://syzkaller.appspot.com/bug?extid=50d41b514809f6f4f326
userspace arch: riscv64

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: [email-masked]

------------[ cut here ]------------
WARNING: CPU: 1 PID: 4475 at kernel/events/core.c:3752 ctx_sched_in+0x12e/0x3ee kernel/events/core.c:3752
Modules linked in:
CPU: 1 PID: 4475 Comm: syz-executor.1 Not tainted 5.12.0-rc6-syzkaller-00183-g79c338ab575e #0
Hardware name: riscv-virtio,qemu (DT)
epc : ctx_sched_in+0x12e/0x3ee kernel/events/core.c:3752
 ra : ctx_sched_in+0x12e/0x3ee kernel/events/core.c:3752
epc : ffffffe000279fe8 ra : ffffffe000279fe8 sp : ffffffe009e17680
 gp : ffffffe004588ad0 tp : ffffffe006398000 t0 : 0000000000000000
 t1 : 0000000000000001 t2 : 00000000000f4240 s0 : ffffffe009e176f0
 s1 : ffffffe0077edc00 a0 : ffffffe067d79118 a1 : 00000000000f0000
 a2 : 0000000000000002 a3 : ffffffe000279fe8 a4 : ffffffe006399000
 a5 : 0000000040000000 a6 : 0000000000f00000 a7 : ffffffe000280cc8
 s2 : 0000000000000007 s3 : ffffffe0077edd40 s4 : ffffffe006398000
 s5 : 0000000000000002 s6 : ffffffe00458c0d0 s7 : ffffffe067d78f70
 s8 : 0000000000000007 s9 : ffffffe067d79118 s10: ffffffe0077edc00
 s11: ffffffe0077edc08 t3 : e189d98bb4bfb900 t4 : ffffffc4042c47b2
 t5 : ffffffc4042c47ba t6 : 0000000000040000
status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003
Call Trace:
[<ffffffe000279fe8>] ctx_sched_in+0x12e/0x3ee kernel/events/core.c:3752
[<ffffffe00027a2e0>] perf_event_sched_in+0x38/0x74 kernel/events/core.c:2680
[<ffffffe000280da2>] perf_event_context_sched_in kernel/events/core.c:3817 [inline]
[<ffffffe000280da2>] __perf_event_task_sched_in+0x4ea/0x680 kernel/events/core.c:3860
[<ffffffe0000850f8>] perf_event_task_sched_in include/linux/perf_event.h:1210 [inline]
[<ffffffe0000850f8>] finish_task_switch.isra.0+0x284/0x318 kernel/sched/core.c:4189
[<ffffffe002a94308>] context_switch kernel/sched/core.c:4325 [inline]
[<ffffffe002a94308>] __schedule+0x484/0xe8c kernel/sched/core.c:5073
[<ffffffe002a95102>] preempt_schedule_notrace+0x9c/0x19a kernel/sched/core.c:5312
[<ffffffe0000cd54a>] rcu_read_unlock_sched_notrace include/linux/rcupdate.h:794 [inline]
[<ffffffe0000cd54a>] trace_lock_acquire+0xf0/0x20e include/trace/events/lock.h:13
[<ffffffe0000d3c0e>] lock_acquire+0x28/0x5a kernel/locking/lockdep.c:5481
[<ffffffe0003b20ee>] rcu_lock_acquire include/linux/rcupdate.h:267 [inline]
[<ffffffe0003b20ee>] rcu_read_lock include/linux/rcupdate.h:656 [inline]
[<ffffffe0003b20ee>] percpu_ref_put_many.constprop.0+0x38/0x148 include/linux/percpu-refcount.h:317
[<ffffffe0003baa56>] percpu_ref_put include/linux/percpu-refcount.h:338 [inline]
[<ffffffe0003baa56>] obj_cgroup_put include/linux/memcontrol.h:713 [inline]
[<ffffffe0003baa56>] memcg_slab_free_hook mm/slab.h:372 [inline]
[<ffffffe0003baa56>] memcg_slab_free_hook mm/slab.h:336 [inline]
[<ffffffe0003baa56>] do_slab_free mm/slub.c:3117 [inline]
[<ffffffe0003baa56>] ___cache_free+0x2bc/0x3dc mm/slub.c:3168
[<ffffffe0003be26c>] qlink_free mm/kasan/quarantine.c:146 [inline]
[<ffffffe0003be26c>] qlist_free_all+0x56/0xac mm/kasan/quarantine.c:165
[<ffffffe0003be774>] kasan_quarantine_reduce+0x14c/0x1c8 mm/kasan/quarantine.c:272
[<ffffffe0003bc3f8>] __kasan_slab_alloc+0x60/0x62 mm/kasan/common.c:437
[<ffffffe0003b8f10>] kasan_slab_alloc include/linux/kasan.h:223 [inline]
[<ffffffe0003b8f10>] slab_post_alloc_hook mm/slab.h:516 [inline]
[<ffffffe0003b8f10>] slab_alloc_node mm/slub.c:2907 [inline]
[<ffffffe0003b8f10>] slab_alloc mm/slub.c:2915 [inline]
[<ffffffe0003b8f10>] kmem_cache_alloc+0x168/0x3ca mm/slub.c:2920
[<ffffffe0001aaee2>] kmem_cache_zalloc include/linux/slab.h:674 [inline]
[<ffffffe0001aaee2>] taskstats_tgid_alloc kernel/taskstats.c:561 [inline]
[<ffffffe0001aaee2>] taskstats_exit+0x3ce/0x5fe kernel/taskstats.c:600
[<ffffffe000031bfc>] do_exit+0x3b2/0x1846 kernel/exit.c:810
[<ffffffe00003319a>] do_group_exit+0xa0/0x198 kernel/exit.c:922
[<ffffffe00004c558>] get_signal+0x31e/0x14ba kernel/signal.c:2781
[<ffffffe000007e06>] do_signal arch/riscv/kernel/signal.c:271 [inline]
[<ffffffe000007e06>] do_notify_resume+0xa8/0x930 arch/riscv/kernel/signal.c:317
[<ffffffe000005586>] ret_from_exception+0x0/0x14

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