netbsd test error: panic: LOCKDEBUG: Reader / writer lock error: rw_vector_tryenter,585: assertion failed: (op != RW_READER && RW_OWNER(rw)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 79a6ddb0 Nix now-unused definitions of MUTEX_GIVE/MUTEX_RE..
git tree: netbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=10bf9c41e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=824b23e1f4b6c76b
dashboard link: https://syzkaller.appspot.com/bug?extid=39816316d9d0c05ce018

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+398163...@syzkaller.appspotmail.com

[ 37.9615453] panic: LOCKDEBUG: Reader / writer lock error:
rw_vector_tryenter,585: assertion failed: (op != RW_READER && RW_OWNER(rw)
== curthread) || (op == RW_READER && RW_COUNT(rw) != 0)
[ 37.9758962] cpu1: Begin traceback...
[ 37.9959288] vpanic() at netbsd:vpanic+0x2aa sys/kern/subr_prf.c:336
[ 38.0560116] snprintf() at netbsd:snprintf
[ 38.1160983] lockdebug_abort1() at netbsd:lockdebug_abort1+0x16a
sys/kern/subr_lockdebug.c:799
[ 38.1861914] rw_abort() at netbsd:rw_abort+0x50 sys/kern/kern_rwlock.c:209
[ 38.2462772] rw_tryenter() at netbsd:rw_tryenter+0x13c
sys/kern/kern_rwlock.c:587
[ 38.3063611] vm_map_lock_try() at netbsd:vm_map_lock_try+0x3c
sys/uvm/uvm_map.c:682
[ 38.3664487] uvm_map_prepare() at netbsd:uvm_map_prepare+0xc0
sys/uvm/uvm_map.c:1170
[ 38.4165183] uvm_map() at netbsd:uvm_map+0xa4 sys/uvm/uvm_map.c:1099
[ 38.4866142] uvm_mmap.part.0() at netbsd:uvm_mmap.part.0+0x32a
[ 38.5466978] sys_mmap() at netbsd:sys_mmap+0x809 uvm_mmap
sys/uvm/uvm_mmap.c:401 [inline]
[ 38.5466978] sys_mmap() at netbsd:sys_mmap+0x809 sys/uvm/uvm_mmap.c:401
[ 38.6067824] sys___syscall() at netbsd:sys___syscall+0x1c8 sy_call
sys/sys/syscallvar.h:65 [inline]
[ 38.6067824] sys___syscall() at netbsd:sys___syscall+0x1c8
sys/kern/sys_syscall.c:77
[ 38.6668679] syscall() at netbsd:syscall+0x29a sy_call
sys/sys/syscallvar.h:65 [inline]
[ 38.6668679] syscall() at netbsd:syscall+0x29a sy_invoke
sys/sys/syscallvar.h:94 [inline]
[ 38.6668679] syscall() at netbsd:syscall+0x29a
sys/arch/x86/x86/syscall.c:138
[ 38.6868956] --- syscall (number 198) ---
[ 38.6868956] Skipping crash dump on recursive panic
[ 38.6969075] panic: UBSan: Undefined Behavior in
/syzkaller/managers/netbsd-kubsan/kernel/sys/arch/amd64/amd64/db_machdep.c:153:24,
member access within misaligned address 0x7 for type 'struct x86_64_frame'
which requires 8 byte alignment

[ 38.7169352] Faulted in mid-traceback; aborting...
[ 38.7169352] fatal breakpoint trap in supervisor mode
[ 38.7269481] trap type 1 code 0 rip 0xffffffff8021ddbd cs 0x8 rflags
0x282 cr2 0x775c19400000 ilevel 0 rsp 0xffff9c00a6b8ccc0
[ 38.7369619] curlwp 0xffffc95592e1dba0 pid 492.3 lowest kstack
0xffff9c00a6b8a2c0
Stopped in pid 492.3 (syz-executor.0) 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
snprintf() at netbsd:snprintf
lockdebug_abort1() at netbsd:lockdebug_abort1+0x16a
sys/kern/subr_lockdebug.c:799
rw_abort() at netbsd:rw_abort+0x50 sys/kern/kern_rwlock.c:209
rw_tryenter() at netbsd:rw_tryenter+0x13c sys/kern/kern_rwlock.c:587
vm_map_lock_try() at netbsd:vm_map_lock_try+0x3c sys/uvm/uvm_map.c:682
uvm_map_prepare() at netbsd:uvm_map_prepare+0xc0 sys/uvm/uvm_map.c:1170
uvm_map() at netbsd:uvm_map+0xa4 sys/uvm/uvm_map.c:1099
uvm_mmap.part.0() at netbsd:uvm_mmap.part.0+0x32a
sys_mmap() at netbsd:sys_mmap+0x809 uvm_mmap sys/uvm/uvm_mmap.c:401 [inline]
sys_mmap() at netbsd:sys_mmap+0x809 sys/uvm/uvm_mmap.c:401
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) ---
[ 38.7469769] Skipping crash dump on recursive panic
[ 38.7469769] panic: UBSan: Undefined Behavior in
/syzkaller/managers/netbsd-kubsan/kernel/sys/arch/amd64/amd64/db_machdep.c:154:14,
member access within misaligned address 0x7 for type 'struct x86_64_frame'
which requires 8 byte alignment

[ 38.7469769] Faulted in mid-traceback; aborting...
[ 38.7469769] fatal breakpoint trap in supervisor mode
[ 38.7469769] trap type 1 code 0 rip 0xffffffff8021ddbd cs 0x8 rflags
0x282 cr2 0x775c19400000 ilevel 0x8 rsp 0xffff9c00a6b8b9c0
[ 38.7469769] curlwp 0xffffc95592e1dba0 pid 492.3 lowest kstack
0xffff9c00a6b8a2c0
Stopped in pid 492.3 (syz-executor.0) at netbsd:breakpoint+0x5:
leave


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[Maxime Villard]

breakage from ad@'s changes, fixed already

#syz invalid