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KCSAN: data-race in css_task_iter_advance / ns_capable_common

Status: auto-closed as invalid on 2020/03/22 06:59
Subsystems: cgroups
[Documentation on labels]
First crash: 1566d, last: 1566d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in css_task_iter_advance / ns_capable_common

read to 0xffff88811dd5a064 of 4 bytes by task 19520 on cpu 1:
 css_task_iter_advance+0x225/0x2c0 kernel/cgroup/cgroup.c:4496
 css_task_iter_start+0xd6/0x110 kernel/cgroup/cgroup.c:4529
 update_tasks_root_domain+0x3b/0xa0 kernel/cgroup/cpuset.c:915
 rebuild_root_domains kernel/cgroup/cpuset.c:951 [inline]
 partition_and_rebuild_sched_domains kernel/cgroup/cpuset.c:965 [inline]
 rebuild_sched_domains_locked kernel/cgroup/cpuset.c:1006 [inline]
 rebuild_sched_domains_locked+0xabb/0xdc0 kernel/cgroup/cpuset.c:980
 update_flag+0x29d/0x2c0 kernel/cgroup/cpuset.c:1902
 cpuset_write_u64+0x14a/0x200 kernel/cgroup/cpuset.c:2276
 cgroup_file_write+0x272/0x320 kernel/cgroup/cgroup.c:3720
 kernfs_fop_write+0x1bd/0x300 fs/kernfs/file.c:315
 __vfs_write+0x67/0xc0 fs/read_write.c:494
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88811dd5a064 of 4 bytes by task 32513 on cpu 0:
 ns_capable_common+0x9f/0xc0 kernel/capability.c:377
 ns_capable+0x29/0x40 kernel/capability.c:396
 do_ip6t_get_ctl+0x63/0x640 net/ipv6/netfilter/ip6_tables.c:1700
 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
 nf_getsockopt+0x71/0xb0 net/netfilter/nf_sockopt.c:122
 ipv6_getsockopt net/ipv6/ipv6_sockglue.c:1400 [inline]
 ipv6_getsockopt+0x17c/0x1d0 net/ipv6/ipv6_sockglue.c:1380
 tcp_getsockopt net/ipv4/tcp.c:3692 [inline]
 tcp_getsockopt+0x7c/0xc0 net/ipv4/tcp.c:3686
 sock_common_getsockopt+0x67/0x90 net/core/sock.c:3108
 __sys_getsockopt+0xf1/0x210 net/socket.c:2162
 __do_sys_getsockopt net/socket.c:2177 [inline]
 __se_sys_getsockopt net/socket.c:2174 [inline]
 __x64_sys_getsockopt+0x70/0x90 net/socket.c:2174
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 32513 Comm: syz-executor.3 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/01/12 06:55 https://github.com/google/ktsan.git kcsan 245a43005292 4c04afaa .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.