syzbot


uvm_fault: kcov_remote_enter (5)

Status: upstream: reported on 2026/03/27 06:03
Reported-by: syzbot+c6fd56998e874294bc2f@syzkaller.appspotmail.com
First crash: 59d, last: 38m
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
openbsd uvm_fault: kcov_remote_enter (3) -1 1 473d 473d 0/3 auto-obsoleted due to no activity on 2025/05/07 03:11
openbsd uvm_fault: kcov_remote_enter (2) -1 2 776d 788d 0/3 auto-obsoleted due to no activity on 2024/07/08 04:34
openbsd uvm_fault: kcov_remote_enter (4) -1 7 166d 168d 0/3 auto-obsoleted due to no activity on 2026/03/09 14:18
openbsd uvm_fault: kcov_remote_enter -1 3 1154d 1272d 0/3 auto-obsoleted due to no activity on 2023/06/25 20:12

Sample crash report:
uvm_fault(0xffffffff839d3278, 0xfffuvm_fault(0xffffffff839d3278, 0xffff800029ee6000, 0, 2) -> e
kernel: page fault trap, code=2
Stopped at      kcov_remote_enter+0x122:        movq    $0,0(%rcx)
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*343333  78441      0           0  0x4000000    0  syz-executor
kcov_remote_enter(0,ffff8000ffff9698) at kcov_remote_enter+0x122 sys/dev/kcov.c:670
timeout_run(ffffffff838c9000,ffff80003c8fbaa8) at timeout_run+0xdf sys/kern/kern_timeout.c:696
softclock_process_tick_timeout(ffff80003c8fbaa8,0) at softclock_process_tick_timeout+0x230 sys/kern/kern_timeout.c:756
softclock(0) at softclock+0x152 sys/kern/kern_timeout.c:788
softintr_dispatch(0) at softintr_dispatch+0xf9 sys/kern/kern_softintr.c:87
dosoftint(0) at dosoftint+0x48 sys/arch/amd64/amd64/intr.c:862
Xsoftclock() at Xsoftclock+0x27
cnputc(66) at cnputc+0x67 sys/dev/cons.c:218
db_putchar(66) at db_putchar+0x36d sys/ddb/db_output.c:155
kprintf() at kprintf+0x29c5 sys/kern/subr_prf.c:-1
db_printf(ffffffff83422841) at db_printf+0x9b sys/kern/subr_prf.c:-1
fault(ffffffff834d9ce9) at fault+0xa3 sys/arch/amd64/amd64/trap.c:161
kpageflttrap(ffff8000380c9820,ffff800029d92004) at kpageflttrap+0x353 sys/arch/amd64/amd64/trap.c:296
kerntrap(ffff8000380c9820) at kerntrap+0x18a sys/arch/amd64/amd64/trap.c:528
end trace frame: 0xffff8000380c98a0, count: 0
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.
ddb> 
ddb> set $lines = 0
ddb> set $maxwidth = 0
ddb> show panic
*cpu0: uvm_fault(0xffffffff839d3278, 0xffff800029ee6000, 0, 2) -> e
ddb> trace
kcov_remote_enter(0,ffff8000ffff9698) at kcov_remote_enter+0x122 sys/dev/kcov.c:670
timeout_run(ffffffff838c9000,ffff80003c8fbaa8) at timeout_run+0xdf sys/kern/kern_timeout.c:696
softclock_process_tick_timeout(ffff80003c8fbaa8,0) at softclock_process_tick_timeout+0x230 sys/kern/kern_timeout.c:756
softclock(0) at softclock+0x152 sys/kern/kern_timeout.c:788
softintr_dispatch(0) at softintr_dispatch+0xf9 sys/kern/kern_softintr.c:87
dosoftint(0) at dosoftint+0x48 sys/arch/amd64/amd64/intr.c:862
Xsoftclock() at Xsoftclock+0x27
cnputc(66) at cnputc+0x67 sys/dev/cons.c:218
db_putchar(66) at db_putchar+0x36d sys/ddb/db_output.c:155
kprintf() at kprintf+0x29c5 sys/kern/subr_prf.c:-1
db_printf(ffffffff83422841) at db_printf+0x9b sys/kern/subr_prf.c:-1
fault(ffffffff834d9ce9) at fault+0xa3 sys/arch/amd64/amd64/trap.c:161
kpageflttrap(ffff8000380c9820,ffff800029d92004) at kpageflttrap+0x353 sys/arch/amd64/amd64/trap.c:296
kerntrap(ffff8000380c9820) at kerntrap+0x18a sys/arch/amd64/amd64/trap.c:528
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
ufs_lookup() at ufs_lookup+0x613 sys/ufs/ufs/ufs_lookup.c:279
VOP_LOOKUP(fffffd80712a56d0,ffff8000380c9c60,ffff8000380c9c90) at VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
vfs_lookup(ffff8000380c9c30) at vfs_lookup+0x94a sys/kern/vfs_lookup.c:580
namei(ffff8000380c9c30) at namei+0x7c3 sys/kern/vfs_lookup.c:250
dosymlinkat(ffff80003c8fad18,200000000000,ffffff9c,200000000040) at dosymlinkat+0xef sys/kern/vfs_syscalls.c:1833
syscall(ffff8000380c9e00) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000380c9e00) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x36f923994d0, count: -22
ddb> 

Crashes (301):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/25 09:53 openbsd 3ca1fbf96c86 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/25 07:14 openbsd 3ca1fbf96c86 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/25 00:56 openbsd 6adc68a286a5 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/24 22:47 openbsd 6adc68a286a5 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/24 19:30 openbsd 6adc68a286a5 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/24 17:24 openbsd 6adc68a286a5 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/24 15:42 openbsd 6adc68a286a5 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/24 13:58 openbsd 6adc68a286a5 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/23 23:52 openbsd 19a448b47c50 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/23 12:05 openbsd 19a8be4fa5c4 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/23 10:40 openbsd 19a8be4fa5c4 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/23 08:55 openbsd dbd5cf8c5e8a c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/23 04:26 openbsd dbd5cf8c5e8a c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/23 02:12 openbsd dbd5cf8c5e8a c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/22 21:28 openbsd dbd5cf8c5e8a c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/22 14:10 openbsd 54bbd1fe416a 95d90255 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/22 03:14 openbsd ca78e759411d 70ae9b03 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/21 21:16 openbsd ca78e759411d 70ae9b03 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/21 11:25 openbsd 19a7e1efad25 747d777d .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/21 09:18 openbsd 19a7e1efad25 747d777d .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/21 07:43 openbsd be9eb1babb0f 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/21 03:49 openbsd be9eb1babb0f 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/20 23:27 openbsd be9eb1babb0f 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/20 21:28 openbsd be9eb1babb0f 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/20 19:08 openbsd 4cd34baf9f06 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/20 07:30 openbsd 4cd34baf9f06 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/19 21:02 openbsd 3fe334830a75 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/18 09:54 openbsd 453e3248fd2d 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/17 17:32 openbsd c52d99c0253a 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/17 14:46 openbsd c52d99c0253a 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/17 07:11 openbsd c057dfdb27e5 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/17 03:59 openbsd c057dfdb27e5 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/17 01:22 openbsd c057dfdb27e5 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/16 16:54 openbsd 501fc77f080e 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/16 05:46 openbsd 25d4b1a85733 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/15 05:30 openbsd 9f6962b18ef0 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/15 02:14 openbsd 9f6962b18ef0 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/14 20:10 openbsd 9f6962b18ef0 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/14 14:02 openbsd 86898828a45d 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/13 22:36 openbsd ed5454cb43ec 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/13 20:20 openbsd ed5454cb43ec 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/05/13 19:09 openbsd ed5454cb43ec 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
2026/03/27 06:02 openbsd 2f434a4256f3 4b3d9a38 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: kcov_remote_enter
* Struck through repros no longer work on HEAD.