KCSAN: data-race in _copy_to_iter / _copy_to

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
030ca497-d507-4949-8b51-0bdbf565ad5c	assessment-security	DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌	❓	KCSAN: data-race in _copy_to_iter / _copy_to_iter (2)	2026/05/29 21:26	2026/05/29 21:26	2026/05/29 22:07	6b4a844333e83556da95d61d7f207e7ef5cd4bc6
2e876699-4f92-4a9a-883f-2d20fe10c85f	assessment-kcsan	Benign: ❌	❓	KCSAN: data-race in _copy_to_iter / _copy_to_iter (2)	2026/05/29 20:53	2026/05/29 20:53	2026/05/29 21:33	6b4a844333e83556da95d61d7f207e7ef5cd4bc6

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[syzbot] [mm?] KCSAN: data-race in _copy_to_iter / _copy_to_iter (2)	0 (1)	2026/05/29 21:34

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[syzbot] [mm?] KCSAN: data-race in _copy_to_iter / _copy_to_iter (2)

0 (1)

2026/05/29 21:34

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in _copy_to_iter / _copy_to_iter mm	6				7	152d	259d	0/29	auto-obsoleted due to no activity on 2026/03/03 09:15

Rank 🛈

upstream

KCSAN: data-race in _copy_to_iter / _copy_to_iter mm

152d

259d

0/29

auto-obsoleted due to no activity on 2026/03/03 09:15

================================================================== BUG: KCSAN: data-race in _copy_to_iter / _copy_to_iter write to 0xffff888131894000 of 1024 bytes by task 49 on cpu 1: memcpy_to_iter lib/iov_iter.c:77 [inline] iterate_bvec include/linux/iov_iter.h:123 [inline] iterate_and_advance2 include/linux/iov_iter.h:306 [inline] iterate_and_advance include/linux/iov_iter.h:330 [inline] _copy_to_iter+0x602/0xea0 lib/iov_iter.c:197 copy_page_to_iter+0x178/0x210 lib/iov_iter.c:374 copy_folio_to_iter include/linux/uio.h:204 [inline] shmem_file_read_iter+0x29e/0x4b0 mm/shmem.c:3426 lo_rw_aio+0x67d/0x730 drivers/block/loop.c:-1 do_req_filebacked drivers/block/loop.c:-1 [inline] loop_handle_cmd drivers/block/loop.c:1925 [inline] loop_process_work+0x56c/0xac0 drivers/block/loop.c:1960 loop_workfn+0x31/0x40 drivers/block/loop.c:1984 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3397 worker_thread+0x58a/0x780 kernel/workqueue.c:3478 kthread+0x22a/0x280 kernel/kthread.c:436 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 read to 0xffff888131894000 of 512 bytes by task 3290 on cpu 0: instrument_copy_to_user include/linux/instrumented.h:130 [inline] copy_to_user_iter lib/iov_iter.c:24 [inline] iterate_ubuf include/linux/iov_iter.h:30 [inline] iterate_and_advance2 include/linux/iov_iter.h:302 [inline] iterate_and_advance include/linux/iov_iter.h:330 [inline] _copy_to_iter+0x130/0xea0 lib/iov_iter.c:197 copy_page_to_iter+0x178/0x210 lib/iov_iter.c:374 copy_folio_to_iter include/linux/uio.h:204 [inline] filemap_read+0x407/0xa10 mm/filemap.c:2857 blkdev_read_iter+0x22d/0x2e0 block/fops.c:855 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x6c0/0x7f0 fs/read_write.c:574 ksys_read+0xdc/0x1a0 fs/read_write.c:717 __do_sys_read fs/read_write.c:726 [inline] __se_sys_read fs/read_write.c:724 [inline] __x64_sys_read+0x40/0x50 fs/read_write.c:724 x64_sys_call+0x2886/0x3020 arch/x86/include/generated/asm/syscalls_64.h:1 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 3290 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 ==================================================================

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/05/27 00:32	upstream	d60ec36cab33	2b01f00e	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in _copy_to_iter / _copy_to_iter

Crashes (1):

Assets (help?)