[syzbot] KASAN: user-memory-access Read in do_syscall_trace_enter

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    18a3c5f7 Merge tag 'for_linus' of git://git.kernel.org/pub..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes
console output: https://syzkaller.appspot.com/x/log.txt?x=14fa7ca5d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=105967f18e189a79
dashboard link: https://syzkaller.appspot.com/bug?extid=e00eb4c4f40728f9bcde
userspace arch: riscv64

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e00eb4c4f40728f9bcde at syzkaller.appspotmail.com

==================================================================
BUG: KASAN: user-memory-access in test_bit include/asm-generic/bitops/non-atomic.h:106 [inline]
BUG: KASAN: user-memory-access in cpumask_test_cpu include/linux/cpumask.h:373 [inline]
BUG: KASAN: user-memory-access in trace_sys_enter include/trace/events/syscalls.h:18 [inline]
BUG: KASAN: user-memory-access in do_syscall_trace_enter+0x24c/0x5ae arch/riscv/kernel/ptrace.c:255
Read of size 8 at addr 000000000118e9ae by task syz-executor.1/3237

CPU: 1 PID: 3237 Comm: syz-executor.1 Not tainted 5.12.0-rc8-syzkaller-00194-g18a3c5f7abfd #0
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
[<ffffffe000009708>] walk_stackframe+0x0/0x23c arch/riscv/kernel/traps.c:202
[<ffffffe002a631dc>] dump_backtrace+0x40/0x4e arch/riscv/kernel/stacktrace.c:113
[<ffffffe002a6320c>] show_stack+0x22/0x2e arch/riscv/kernel/stacktrace.c:118
[<ffffffe002a6ca98>] __dump_stack lib/dump_stack.c:79 [inline]
[<ffffffe002a6ca98>] dump_stack+0x148/0x1d8 lib/dump_stack.c:120
[<ffffffe0003bd560>] __kasan_report mm/kasan/report.c:403 [inline]
[<ffffffe0003bd560>] kasan_report+0x146/0x18c mm/kasan/report.c:416
[<ffffffe0003bddc8>] check_region_inline mm/kasan/generic.c:174 [inline]
[<ffffffe0003bddc8>] __asan_load8+0x4a/0x80 mm/kasan/generic.c:253
[<ffffffe000006fe8>] test_bit include/asm-generic/bitops/non-atomic.h:106 [inline]
[<ffffffe000006fe8>] cpumask_test_cpu include/linux/cpumask.h:373 [inline]
[<ffffffe000006fe8>] trace_sys_enter include/trace/events/syscalls.h:18 [inline]
[<ffffffe000006fe8>] do_syscall_trace_enter+0x24c/0x5ae arch/riscv/kernel/ptrace.c:255
[<ffffffe000005664>] handle_syscall_trace_enter+0x6/0x1e
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
SMP: stopping secondary CPUs
Rebooting in 86400 seconds..


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