[syzbot] general protection fault in cgroup_rstat_flush_locked

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    d0c0fe10 bpf: Avoid using ARRAY_SIZE on an uninitialized p..
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=13817145d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5b86a12e0d1933b5
dashboard link: https://syzkaller.appspot.com/bug?extid=363f98e1c445bd838351

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+363f98e1c445bd838351@xxxxxxxxxxxxxxxxxxxxxxxxx

general protection fault, probably for non-canonical address 0xdffffc0000000077: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000003b8-0x00000000000003bf]
CPU: 1 PID: 26368 Comm: kworker/1:4 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: cgroup_destroy css_release_work_fn
RIP: 0010:cgroup_rstat_cpu kernel/cgroup/rstat.c:13 [inline]
RIP: 0010:cgroup_rstat_cpu_pop_updated kernel/cgroup/rstat.c:106 [inline]
RIP: 0010:cgroup_rstat_flush_locked+0x182/0xcc0 kernel/cgroup/rstat.c:161
Code: 85 f6 49 89 f4 48 89 44 24 10 75 0a e9 94 06 00 00 4c 8b 64 24 08 e8 cd f5 05 00 4d 8d bc 24 78 03 00 00 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 6b 08 00 00 49 8b 9c 24 78 03 00 00 48 83 3c
RSP: 0018:ffffc900027a7c20 EFLAGS: 00010007
RAX: 0000000000000077 RBX: ffffe8ffffc82510 RCX: 0000000000000000
RDX: ffff88802723d4c0 RSI: ffffffff816ed0a3 RDI: ffffe8ffffc82540
RBP: ffff888037f5c000 R08: 0000000000000001 R09: 0000000000000003
R10: fffff520004f4f76 R11: 0000000000000000 R12: 0000000000000046
R13: dffffc0000000000 R14: ffff8880b9c00000 R15: 00000000000003be
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33a2a000 CR3: 000000005e401000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 cgroup_rstat_flush+0x3a/0x50 kernel/cgroup/rstat.c:203
 css_release_work_fn+0x440/0x920 kernel/cgroup/cgroup.c:4991
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Modules linked in:
---[ end trace c2ed221e705dd64b ]---
RIP: 0010:cgroup_rstat_cpu kernel/cgroup/rstat.c:13 [inline]
RIP: 0010:cgroup_rstat_cpu_pop_updated kernel/cgroup/rstat.c:106 [inline]
RIP: 0010:cgroup_rstat_flush_locked+0x182/0xcc0 kernel/cgroup/rstat.c:161
Code: 85 f6 49 89 f4 48 89 44 24 10 75 0a e9 94 06 00 00 4c 8b 64 24 08 e8 cd f5 05 00 4d 8d bc 24 78 03 00 00 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 6b 08 00 00 49 8b 9c 24 78 03 00 00 48 83 3c
RSP: 0018:ffffc900027a7c20 EFLAGS: 00010007
RAX: 0000000000000077 RBX: ffffe8ffffc82510 RCX: 0000000000000000
RDX: ffff88802723d4c0 RSI: ffffffff816ed0a3 RDI: ffffe8ffffc82540
RBP: ffff888037f5c000 R08: 0000000000000001 R09: 0000000000000003
R10: fffff520004f4f76 R11: 0000000000000000 R12: 0000000000000046
R13: dffffc0000000000 R14: ffff8880b9c00000 R15: 00000000000003be
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33a2a000 CR3: 000000005e401000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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