From 2f26ed1764b42a8c40d9c48441c73a70d805decf Mon Sep 17 00:00:00 2001 From: Daniel Axtens Date: Fri, 29 May 2020 16:14:46 +1000 Subject: [PATCH] powerpc/64s: Disable sanitisers for C syscall/interrupt entry/exit code 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 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 ...... This is caused by __sanitizer_cov_trace_pc() causing an SLB fault after MSR[RI] has been cleared by __hard_EE_RI_disable(), which we can not recover from. Do not instrument the new syscall/interrupt entry/exit code with KCOV, GCOV or UBSAN. Reported-by: syzbot-ppc64 Fixes: 68b34588e202 ("powerpc/64/sycall: Implement syscall entry/exit logic in C") Signed-off-by: Daniel Axtens Acked-by: Andrew Donnellan Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/Makefile | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 1c43858..244542a 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -162,6 +162,9 @@ UBSAN_SANITIZE_kprobes.o := n GCOV_PROFILE_kprobes-ftrace.o := n KCOV_INSTRUMENT_kprobes-ftrace.o := n UBSAN_SANITIZE_kprobes-ftrace.o := n +GCOV_PROFILE_syscall_64.o := n +KCOV_INSTRUMENT_syscall_64.o := n +UBSAN_SANITIZE_syscall_64.o := n UBSAN_SANITIZE_vdso.o := n # Necessary for booting with kcov enabled on book3e machines -- 2.7.4