syzbot


KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn (6)

Status: auto-obsoleted due to no activity on 2023/08/21 13:19
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+443f491a1ce0d21e2d75@syzkaller.appspotmail.com
First crash: 357d, last: 316d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn (5) bpf net 21 396d 650d 0/26 auto-obsoleted due to no activity on 2023/06/02 17:22
upstream KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn net 4 1429d 1439d 0/26 auto-closed as invalid on 2020/08/04 06:35
upstream KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn (2) net 3 1343d 1378d 0/26 auto-closed as invalid on 2020/10/28 20:02
upstream KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn (9) kernel 4 102d 140d 0/26 auto-obsoleted due to no activity on 2024/03/23 07:08
upstream KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn (4) bpf 12 725d 896d 0/26 auto-closed as invalid on 2022/07/08 11:31
upstream KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn (3) bpf 12 1149d 1246d 0/26 auto-closed as invalid on 2021/05/17 09:01
upstream KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn (8) kernel 6 184d 171d 0/26 auto-obsoleted due to no activity on 2023/12/31 20:24
upstream KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn (7) kernel 1 244d 244d 0/26 auto-obsoleted due to no activity on 2023/11/01 12:19

Sample crash report:
==================================================================
BUG: KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn

read-write to 0xffffffff86f8615c of 4 bytes by task 3067 on cpu 1:
 pcpu_update_empty_pages mm/percpu.c:602 [inline]
 pcpu_chunk_populated mm/percpu.c:1531 [inline]
 pcpu_balance_populated mm/percpu.c:2088 [inline]
 pcpu_balance_workfn+0x96f/0xa80 mm/percpu.c:2238
 process_one_work+0x434/0x860 kernel/workqueue.c:2597
 worker_thread+0x5f2/0xa10 kernel/workqueue.c:2748
 kthread+0x1d7/0x210 kernel/kthread.c:389
 ret_from_fork+0x2e/0x40 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:296

read to 0xffffffff86f8615c of 4 bytes by task 4000 on cpu 0:
 pcpu_alloc+0xa59/0x1280 mm/percpu.c:1870
 __alloc_percpu_gfp+0x26/0x30 mm/percpu.c:1930
 bpf_map_alloc_percpu+0xaa/0x200 kernel/bpf/syscall.c:464
 htab_map_alloc+0x37b/0xde0 kernel/bpf/hashtab.c:521
 map_create+0x713/0xa60 kernel/bpf/syscall.c:1206
 __sys_bpf+0x62a/0x780 kernel/bpf/syscall.c:5119
 __do_sys_bpf kernel/bpf/syscall.c:5241 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5239 [inline]
 __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5239
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000 -> 0xfffffffc

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4000 Comm: syz-executor.3 Not tainted 6.5.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
==================================================================

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/07/17 13:19 upstream fdf0eaf11452 20f8b3c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn
2023/07/11 14:51 upstream 3f01e9fed845 2f19aa4f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn
2023/07/07 02:35 upstream a452483508d7 22ae5830 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn
2023/06/18 18:15 upstream 8c1f0c38b310 f3921d4d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn
2023/06/17 02:39 upstream 1639fae5132b f3921d4d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn
2023/06/09 14:45 upstream 33f2b5785a2b 9018a337 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn
2023/06/06 14:06 upstream a4d7d7011219 a4ae4f42 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn
* Struck through repros no longer work on HEAD.