From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Daniel Axtens <dja@axtens.net>,
linuxppc-dev@lists.ozlabs.org, npiggin@gmail.com
Cc: ajd@linux.ibm.com, Daniel Axtens <dja@axtens.net>
Subject: Re: [PATCH] powerpc/64/syscall: Disable sanitisers for C syscall entry/exit code
Date: Tue, 2 Jun 2020 15:25:43 +1000 (AEST) [thread overview]
Message-ID: <49bgVc0ql9z9sSg@ozlabs.org> (raw)
In-Reply-To: <20200529061446.2773-1-dja@axtens.net>
On Fri, 2020-05-29 at 06:14:46 UTC, Daniel Axtens wrote:
> syzkaller is picking up a bunch of crashes that look like this:
>
> Unrecoverable exception 380 at c00000000037ed60 (msr=8000000000001031)
> Oops: Unrecoverable exception, sig: 6 [#1]
> LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
> Modules linked in:
> CPU: 0 PID: 874 Comm: syz-executor.0 Not tainted 5.7.0-rc7-syzkaller-00016-gb0c3ba31be3e #0
> NIP: c00000000037ed60 LR: c00000000004bac8 CTR: c000000000030990
> REGS: c0000000555a7230 TRAP: 0380 Not tainted (5.7.0-rc7-syzkaller-00016-gb0c3ba31be3e)
> MSR: 8000000000001031 <SF,ME,IR,DR,LE> CR: 48222882 XER: 20000000
> CFAR: c00000000004bac4 IRQMASK: 0
> GPR00: c00000000004bb68 c0000000555a74c0 c0000000024b3500 0000000000000005
> GPR04: 0000000000000000 0000000000000000 c00000000004bb88 c008000000910000
> GPR08: 00000000000b0000 c00000000004bac8 0000000000016000 c000000002503500
> GPR12: c000000000030990 c000000003190000 00000000106a5898 00000000106a0000
> GPR16: 00000000106a5890 c000000007a92000 c000000008180e00 c000000007a8f700
> GPR20: c000000007a904b0 0000000010110000 c00000000259d318 5deadbeef0000100
> GPR24: 5deadbeef0000122 c000000078422700 c000000009ee88b8 c000000078422778
> GPR28: 0000000000000001 800000000280b033 0000000000000000 c0000000555a75a0
> NIP [c00000000037ed60] __sanitizer_cov_trace_pc+0x40/0x50
> LR [c00000000004bac8] interrupt_exit_kernel_prepare+0x118/0x310
> Call Trace:
> [c0000000555a74c0] [c00000000004bb68] interrupt_exit_kernel_prepare+0x1b8/0x310 (unreliable)
> [c0000000555a7530] [c00000000000f9a8] interrupt_return+0x118/0x1c0
> --- interrupt: 900 at __sanitizer_cov_trace_pc+0x0/0x50
> ...<random previous call chain>...
>
> That looks like the KCOV helper accessing memory that's not safe to
> access in the interrupt handling context.
>
> Do not instrument the new syscall entry/exit code with KCOV, GCOV or
> UBSAN.
>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Fixes: 68b34588e202 ("powerpc/64/sycall: Implement syscall entry/exit logic in C")
> Signed-off-by: Daniel Axtens <dja@axtens.net>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/2f26ed1764b42a8c40d9c48441c73a70d805decf
cheers
prev parent reply other threads:[~2020-06-02 5:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-29 6:14 [PATCH] powerpc/64/syscall: Disable sanitisers for C syscall entry/exit code Daniel Axtens
2020-05-29 8:24 ` Andrew Donnellan
2020-05-29 11:14 ` Michael Ellerman
2020-06-02 5:25 ` Michael Ellerman [this message]
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