UBSan: Undefined Behavior in db_nextframe (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 23ee83f7c0ae c.7: mention that C11 and C17 have been publi..
git tree: netbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=147026fae80000
kernel config: https://syzkaller.appspot.com/x/.config?x=1420f906d33d9f1f
dashboard link: https://syzkaller.appspot.com/bug?extid=98d7765a8ad17a5349e9
compiler: g++ (Debian 12.2.0-14) 12.2.0

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eec3acfd0e7f/disk-23ee83f7.raw.xz
netbsd.gdb: https://storage.googleapis.com/syzbot-assets/155e6a968a41/netbsd-23ee83f7.gdb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+98d776...@syzkaller.appspotmail.com

[ 463.8604478] panic: cpu1: time has not advanced in 1501 heartbeats
[ 463.8604478] cpu1: Begin traceback...
[ 463.8604478] vpanic() at netbsd:vpanic+0x2f0 sys/kern/subr_prf.c:292
[ 463.8604478] panic() at netbsd:panic+0x49 sys/kern/subr_prf.c:1120
[ 463.8604478] heartbeat() at netbsd:heartbeat+0x480 select_patient sys/kern/kern_heartbeat.c:513 [inline]
[ 463.8604478] heartbeat() at netbsd:heartbeat+0x480 sys/kern/kern_heartbeat.c:632
[ 463.8604478] hardclock() at netbsd:hardclock+0x1d9 sys/kern/kern_clock.c:351
[ 463.8604478] Skipping crash dump on recursive panic
[ 463.8604478] panic: UBSan: Undefined Behavior in /syzkaller/managers/ci2-netbsd-kubsan/kernel/sys/arch/amd64/amd64/db_machdep.c:125:24, member access within misaligned address 0x4026a2 for type 'struct x86_64_frame' which requires 8 byte alignment

[ 463.8604478] Faulted in mid-traceback; aborting...
[ 463.8604478] fatal breakpoint trap in supervisor mode
[ 463.8604478] trap type 1 code 0 rip 0xffffffff80235485 cs 0x8 rflags 0x246 cr2 0x7713cdea7000 ilevel 0x7 rsp 0xffff9e02544f5070
[ 463.8604478] curlwp 0xffffe4457d4988c0 pid 6456.6456 lowest kstack 0xffff9e02544f12c0
Stopped in pid 6456.6456 (syz-executor.2) at netbsd:breakpoint+0x5: leave
?
breakpoint() at netbsd:breakpoint+0x5
db_panic() at netbsd:db_panic+0xec sys/ddb/db_panic.c:69
vpanic() at netbsd:vpanic+0x2f0 sys/kern/subr_prf.c:292
Report() at netbsd:Report+0x3b sys/../common/lib/libc/misc/ubsan.c:1352
HandleTypeMismatch() at netbsd:HandleTypeMismatch+0xfc sys/../common/lib/libc/misc/ubsan.c:432
db_nextframe() at netbsd:db_nextframe+0x790 sys/arch/amd64/amd64/db_machdep.c:125
db_stack_trace_print() at netbsd:db_stack_trace_print+0x281 sys/arch/x86/x86/db_trace.c:278
db_panic() at netbsd:db_panic+0x9d x86_curcpu sys/arch/amd64/compile/obj/GENERIC_SYZKALLER/./machine/cpu.h:56 [inline]
db_panic() at netbsd:db_panic+0x9d sys/ddb/db_panic.c:59
vpanic() at netbsd:vpanic+0x2f0 sys/kern/subr_prf.c:292
panic() at netbsd:panic+0x49 sys/kern/subr_prf.c:1120
heartbeat() at netbsd:heartbeat+0x480 select_patient sys/kern/kern_heartbeat.c:513 [inline]
heartbeat() at netbsd:heartbeat+0x480 sys/kern/kern_heartbeat.c:632
hardclock() at netbsd:hardclock+0x1d9 sys/kern/kern_clock.c:351
[ 463.8604478] Skipping crash dump on recursive panic
[ 463.8604478] panic: UBSan: Undefined Behavior in /syzkaller/managers/ci2-netbsd-kubsan/kernel/sys/arch/amd64/amd64/db_machdep.c:126:14, member access within misaligned address 0x4026a2 for type 'struct x86_64_frame' which requires 8 byte alignment

[ 463.8604478] Faulted in mid-traceback; aborting...
[ 463.8604478] fatal breakpoint trap in supervisor mode
[ 463.8604478] trap type 1 code 0 rip 0xffffffff80235485 cs 0x8 rflags 0x246 cr2 0x7713cdea7000 ilevel 0x8 rsp 0xffff9e02544f3d70
[ 463.8604478] curlwp 0xffffe4457d4988c0 pid 6456.6456 lowest kstack 0xffff9e02544f12c0
Stopped in pid 6456.6456 (syz-executor.2) at netbsd:breakpoint+0x5: leave


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.