panic: UBSan: Undefined Behavior in /syzkaller/managers/netbsd-kubsan/kernel/sys/arch/amd64/amd64/process_machdep.c:LIN

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 67964b7d There are some devices on the bcm283x that share ..
git tree: netbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=11b890dee00000
kernel config: https://syzkaller.appspot.com/x/.config?x=824b23e1f4b6c76b
dashboard link: https://syzkaller.appspot.com/bug?extid=fd3f85c337e32855619f

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+fd3f85...@syzkaller.appspotmail.com

�
[
58.3754770]
panic: UBSan: Undefined Behavior in
/syzkaller/managers/netbsd-kubsan/kernel/sys/arch/amd64/amd64/process_machdep. c:159:2,
member access within misaligned address 0xffffca80b3af48c8 for type 'struct
fpreg' which requires 16 byte alignment

[ 58.3951521] cpu1: Begin traceback...
[
58.4251958]
vpanic() at
netbsd:vpanic+0x2aa
[
58.4852625]
isAlreadyReported() at netbsd:isAlreadyReported
[ 58.5353201] HandleTypeMismatch.part.1() at
netbsd:HandleTypeMismatch.part.1+0xcc
[ 58.5953950] HandleTypeMismatch() at netbsd:HandleTypeMismatch+0x7b
sys/../common/lib/libc/misc/ubsan.c:408
[ 58.6554676] process_read_fpregs() at netbsd:process_read_fpregs+0x3d
sys/arch/amd64/amd64/process_machdep.c:159
[ 58.7155434] proc_regio() at netbsd:proc_regio+0x164
sys/kern/sys_ptrace_common.c:1478
[ 58.7756177] process_dofpregs() at netbsd:process_dofpregs+0xa7
sys/kern/sys_ptrace_common.c:1566
[ 58.8256808] do_ptrace() at netbsd:do_ptrace+0x12d6 ptrace_regs
sys/kern/sys_ptrace_common.c:897 [inline]
[ 58.8256808] do_ptrace() at netbsd:do_ptrace+0x12d6
sys/kern/sys_ptrace_common.c:1429
[ 58.8757438] sys_ptrace() at netbsd:sys_ptrace+0x4f
sys/kern/sys_ptrace.c:218
[ 58.9358216] sys___syscall() at netbsd:sys___syscall+0x1c8 sy_call
sys/sys/syscallvar.h:65 [inline]
[ 58.9358216] sys___syscall() at netbsd:sys___syscall+0x1c8
sys/kern/sys_syscall.c:77
[ 58.9958957] syscall() at netbsd:syscall+0x29a sy_call
sys/sys/syscallvar.h:65 [inline]
[ 58.9958957] syscall() at netbsd:syscall+0x29a sy_invoke
sys/sys/syscallvar.h:94 [inline]
[ 58.9958957] syscall() at netbsd:syscall+0x29a
sys/arch/x86/x86/syscall.c:138
[ 59.0059100] --- syscall (number 198) ---
[ 59.0159214] Skipping crash dump on recursive panic
[ 59.0159214] panic: UBSan: Undefined Behavior in
/syzkaller/managers/netbsd-kubsan/kernel/sys/arch/amd64/amd64/db_machdep.c:153:24,
member access within misaligned address 0x4 for type 'struct x86_64_frame'
which requires 8 byte alignment

[ 59.0359411] Faulted in mid-traceback; aborting...
[ 59.0459519] fatal breakpoint trap in supervisor mode
[ 59.0459519] trap type 1 code 0 rip 0xffffffff8021ddbd cs 0x8 rflags
0x286 cr2 0x200001c0 ilevel 0 rsp 0xffffca80b3af34b0
[ 59.0559644] curlwp 0xffff98b07c99d180 pid 200.3 lowest kstack
0xffffca80b3af12c0
Stopped in pid 200.3 (syz-executor.2) at netbsd:breakpoint+0x5:
leave
?
breakpoint() at netbsd:breakpoint+0x5
db_panic() at netbsd:db_panic+0x109 sys/ddb/db_panic.c:67
vpanic() at netbsd:vpanic+0x2aa sys/kern/subr_prf.c:336
isAlreadyReported() at netbsd:isAlreadyReported
HandleTypeMismatch.part.1() at netbsd:HandleTypeMismatch.part.1+0xcc
HandleTypeMismatch() at netbsd:HandleTypeMismatch+0x7b
sys/../common/lib/libc/misc/ubsan.c:408
db_nextframe() at netbsd:db_nextframe+0x6f6
sys/arch/amd64/amd64/db_machdep.c:153
db_stack_trace_print() at netbsd:db_stack_trace_print+0x2c4
sys/arch/x86/x86/db_trace.c:277
db_panic() at netbsd:db_panic+0xa3 x86_curcpu
sys/arch/amd64/compile/obj/GENERIC_SYZKALLER/./machine/cpu.h:67 [inline]
db_panic() at netbsd:db_panic+0xa3 sys/ddb/db_panic.c:57
vpanic() at netbsd:vpanic+0x2aa sys/kern/subr_prf.c:336
isAlreadyReported() at netbsd:isAlreadyReported
HandleTypeMismatch.part.1() at netbsd:HandleTypeMismatch.part.1+0xcc
HandleTypeMismatch() at netbsd:HandleTypeMismatch+0x7b
sys/../common/lib/libc/misc/ubsan.c:408
process_read_fpregs() at netbsd:process_read_fpregs+0x3d
sys/arch/amd64/amd64/process_machdep.c:159
proc_regio() at netbsd:proc_regio+0x164 sys/kern/sys_ptrace_common.c:1478
process_dofpregs() at netbsd:process_dofpregs+0xa7
sys/kern/sys_ptrace_common.c:1566
do_ptrace() at netbsd:do_ptrace+0x12d6 ptrace_regs
sys/kern/sys_ptrace_common.c:897 [inline]
do_ptrace() at netbsd:do_ptrace+0x12d6 sys/kern/sys_ptrace_common.c:1429
sys_ptrace() at netbsd:sys_ptrace+0x4f sys/kern/sys_ptrace.c:218
sys___syscall() at netbsd:sys___syscall+0x1c8 sy_call
sys/sys/syscallvar.h:65 [inline]
sys___syscall() at netbsd:sys___syscall+0x1c8 sys/kern/sys_syscall.c:77
syscall() at netbsd:syscall+0x29a sy_call sys/sys/syscallvar.h:65 [inline]
syscall() at netbsd:syscall+0x29a sy_invoke sys/sys/syscallvar.h:94 [inline]
syscall() at netbsd:syscall+0x29a sys/arch/x86/x86/syscall.c:138
--- syscall (number 198) ---
[ 59.0659777] Skipping crash dump on recursive panic
[ 59.0659777] panic: UBSan: Undefined Behavior in
/syzkaller/managers/netbsd-kubsan/kernel/sys/arch/amd64/amd64/db_machdep.c:154:14,
member access within misaligned address 0x4 for type 'struct x86_64_frame'
which requires 8 byte alignment

[ 59.0659777] Faulted in mid-traceback; aborting...
[ 59.0659777] fatal breakpoint trap in supervisor mode
[ 59.0659777] trap type 1 code 0 rip 0xffffffff8021ddbd cs 0x8 rflags
0x286 cr2 0x200001c0 ilevel 0x8 rsp 0xffffca80b3af21b0
[ 59.0659777] curlwp 0xffff98b07c99d180 pid 200.3 lowest kstack
0xffffca80b3af12c0
Stopped in pid 200.3 (syz-executor.2) at netbsd:breakpoint+0x5:
leave


---
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[Maxime Villard]

dup but garbage, close

#syz invalid