syzbot


KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath

Status: moderation: reported on 2026/01/19 04:38
Subsystems: kernfs
[Documentation on labels]
Reported-by: syzbot+f5e0ba366db50663c2e2@syzkaller.appspotmail.com
First crash: 77d, last: 1d01h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
ee12a410-8059-4965-a91c-3df09e94e9e6 repro KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath 2026/03/10 13:38 2026/03/11 03:47 2026/03/11 03:57 86914af9098a80da53c3c5d46be980c572ee29f8
e2847366-3443-4665-896c-c81e8a820dad assessment-kcsan Benign: ✅  Confident: ✅  KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath 2026/01/19 04:37 2026/01/19 04:37 2026/01/19 04:41 a9d6a79219801d2130df3b1a792c57f0e5428e9f

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

write to 0xffffc9000165b9e8 of 1 bytes by task 8956 on cpu 1:
 rwsem_try_write_lock kernel/locking/rwsem.c:653 [inline]
 rwsem_down_write_slowpath+0x3c9/0xa90 kernel/locking/rwsem.c:1159
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0xab/0xc0 kernel/locking/rwsem.c:1591
 kernfs_activate+0x50/0x220 fs/kernfs/dir.c:1430
 kernfs_add_one+0x212/0x280 fs/kernfs/dir.c:839
 __kernfs_create_file+0x145/0x180 fs/kernfs/file.c:1086
 sysfs_add_file_mode_ns+0x132/0x1b0 fs/sysfs/file.c:313
 create_files fs/sysfs/group.c:82 [inline]
 internal_create_group+0x441/0x9e0 fs/sysfs/group.c:189
 internal_create_groups fs/sysfs/group.c:229 [inline]
 sysfs_create_groups+0x3f/0xf0 fs/sysfs/group.c:255
 setup_gid_attrs drivers/infiniband/core/sysfs.c:1118 [inline]
 ib_setup_port_attrs+0xe89/0x1400 drivers/infiniband/core/sysfs.c:1394
 add_one_compat_dev+0x297/0x390 drivers/infiniband/core/device.c:977
 rdma_dev_init_net+0x1b9/0x240 drivers/infiniband/core/device.c:1193
 ops_init+0x22a/0x2e0 net/core/net_namespace.c:137
 setup_net+0x9f/0x230 net/core/net_namespace.c:446
 copy_net_ns+0x310/0x450 net/core/net_namespace.c:581
 create_new_namespaces+0x20e/0x440 kernel/nsproxy.c:130
 unshare_nsproxy_namespaces+0xe6/0x120 kernel/nsproxy.c:226
 ksys_unshare+0x3f2/0x6f0 kernel/fork.c:3173
 __do_sys_unshare kernel/fork.c:3244 [inline]
 __se_sys_unshare kernel/fork.c:3242 [inline]
 __x64_sys_unshare+0x1f/0x30 kernel/fork.c:3242
 x64_sys_call+0x1cef/0x3020 arch/x86/include/generated/asm/syscalls_64.h:273
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffc9000165b9e8 of 1 bytes by task 8961 on cpu 0:
 rwsem_down_write_slowpath+0x43d/0xa90 kernel/locking/rwsem.c:1177
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0xab/0xc0 kernel/locking/rwsem.c:1591
 kernfs_activate+0x50/0x220 fs/kernfs/dir.c:1430
 kernfs_add_one+0x212/0x280 fs/kernfs/dir.c:839
 __kernfs_create_file+0x145/0x180 fs/kernfs/file.c:1086
 sysfs_add_file_mode_ns+0x132/0x1b0 fs/sysfs/file.c:313
 create_files fs/sysfs/group.c:82 [inline]
 internal_create_group+0x441/0x9e0 fs/sysfs/group.c:189
 internal_create_groups fs/sysfs/group.c:229 [inline]
 sysfs_create_groups+0x3f/0xf0 fs/sysfs/group.c:255
 device_add_groups drivers/base/core.c:2837 [inline]
 device_add_attrs+0xf4/0x3f0 drivers/base/core.c:2912
 device_add+0x37a/0x770 drivers/base/core.c:3645
 wakeup_source_device_create drivers/base/power/wakeup_stats.c:163 [inline]
 wakeup_source_sysfs_add+0x15a/0x1d0 drivers/base/power/wakeup_stats.c:183
 wakeup_source_register+0xfd/0x240 drivers/base/power/wakeup.c:218
 ep_create_wakeup_source fs/eventpoll.c:1495 [inline]
 ep_insert+0x82f/0xe00 fs/eventpoll.c:1630
 do_epoll_ctl+0x686/0x8a0 fs/eventpoll.c:2341
 __do_sys_epoll_ctl fs/eventpoll.c:2392 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2383 [inline]
 __x64_sys_epoll_ctl+0xcb/0x100 fs/eventpoll.c:2383
 x64_sys_call+0x2a8b/0x3020 arch/x86/include/generated/asm/syscalls_64.h:234
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 8961 Comm: syz.3.1621 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
==================================================================

Crashes (38):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/05 21:51 upstream 1791c390149f 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/04/04 22:01 upstream 7ca6d1cfec80 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/04/03 23:13 upstream d8a9a4b11a13 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/04/01 11:36 upstream dbf00d8d23b4 9a1f7828 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/31 08:47 upstream d0c3bcd5b897 d0af506e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/30 21:53 upstream 7aaa8047eafd d0af506e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/26 04:30 upstream d2a43e7f89da c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/23 21:40 upstream c369299895a5 4933dba2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/23 02:47 upstream ec69c9e88315 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/22 14:43 upstream 113ae7b4decc 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/20 06:13 upstream 8a30aeb0d1b4 2f245add .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/11 12:39 upstream b4f0dd314b39 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/09 23:45 upstream 1f318b96cc84 176bead5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/09 11:59 upstream 1f318b96cc84 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/09 02:48 upstream 014441d1e4b2 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/08 04:36 upstream c23719abc330 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/07 16:48 upstream 4ae12d8bd9a8 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/06 19:05 upstream 5ee8dbf54602 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/05 18:14 upstream c107785c7e8d d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/05 18:14 upstream c107785c7e8d d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/05 04:47 upstream ecc64d2dc9ff a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/04 09:04 upstream 0031c06807cf 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/02 18:35 upstream 11439c4635ed b9dd6534 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/03/01 21:53 upstream 39c633261414 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/02/24 01:06 upstream 7dff99b35460 41d2fa6a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/02/22 22:03 upstream 32a92f8c8932 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/02/16 21:40 upstream 0f2acd3148e0 5d52cba5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/02/16 03:36 upstream 26a4cfaff82a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/02/15 07:51 upstream 3e48a11675c5 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/02/12 03:56 upstream c22e26bd0906 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/02/09 11:15 upstream 05f7e89ab973 df949cd9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/01/31 23:12 upstream ad9a728a3388 afc0c4d4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/01/30 01:56 upstream 4d310797262f bfa73b7b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/01/29 12:45 upstream 8dfce8991b95 aeb6fdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/01/28 02:29 upstream 1f97d9dcf536 3029c699 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/01/27 11:30 upstream fcb70a56f4d8 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/01/27 04:30 upstream fcb70a56f4d8 efb3e894 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
2026/01/19 04:37 upstream e84d960149e7 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath
* Struck through repros no longer work on HEAD.