KCSAN: data-race in userfaultfd_ioctl / userfaultfd

Kernel	Title	Rank 🛈	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (3) mm fs	6	1	2128d	2128d	0/29	auto-closed as invalid on 2020/05/10 10:19
upstream	KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (6) mm fs	6	1	1846d	1846d	0/29	auto-closed as invalid on 2021/01/11 23:50
upstream	KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (4) fs mm	6	1	1936d	1936d	0/29	auto-closed as invalid on 2020/10/14 02:21
upstream	KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (5) mm fs	6	2	1884d	1889d	0/29	auto-closed as invalid on 2020/12/04 12:11
upstream	KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (2) fs mm	6	1	2225d	2225d	0/29	closed as invalid on 2020/01/09 14:13

================================================================== BUG: KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl write to 0xffff88809eb6b570 of 4 bytes by task 17499 on cpu 0: userfaultfd_api fs/userfaultfd.c:1850 [inline] userfaultfd_ioctl+0x17c2/0x24d0 fs/userfaultfd.c:1869 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x991/0xc60 fs/ioctl.c:696 ksys_ioctl+0xbd/0xe0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x4c/0x60 fs/ioctl.c:718 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff88809eb6b570 of 4 bytes by task 17502 on cpu 1: userfaultfd_ioctl+0x70/0x24d0 fs/userfaultfd.c:1864 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x991/0xc60 fs/ioctl.c:696 ksys_ioctl+0xbd/0xe0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x4c/0x60 fs/ioctl.c:718 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 17502 Comm: syz-executor.2 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ================================================================== Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 17502 Comm: syz-executor.2 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xf5/0x159 lib/dump_stack.c:113 panic+0x210/0x640 kernel/panic.c:221 kcsan_report.cold+0xc/0x10 kernel/kcsan/report.c:302 __kcsan_setup_watchpoint+0x32e/0x4a0 kernel/kcsan/core.c:411 __tsan_read4 kernel/kcsan/kcsan.c:35 [inline] __tsan_read4+0x2c/0x30 kernel/kcsan/kcsan.c:35 userfaultfd_ioctl+0x70/0x24d0 fs/userfaultfd.c:1864 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x991/0xc60 fs/ioctl.c:696 ksys_ioctl+0xbd/0xe0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x4c/0x60 fs/ioctl.c:718 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x459ef9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f563583ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459ef9 RDX: 0000000020000300 RSI: 00000000c020aa00 RDI: 0000000000000004 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f563583b6d4 R13: 00000000004c4d64 R14: 00000000004d97b0 R15: 00000000ffffffff Kernel Offset: disabled Rebooting in 86400 seconds..