Commit a494d3c8 authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google) Committed by Steven Rostedt
Browse files

ring-buffer: Flush and stop persistent ring buffer on panic 

On real hardware, panic and machine reboot may not flush hardware cache
to memory. This means the persistent ring buffer, which relies on a
coherent state of memory, may not have its events written to the buffer
and they may be lost. Moreover, there may be inconsistency with the
counters which are used for validation of the integrity of the
persistent ring buffer which may cause all data to be discarded.

To avoid this issue, stop recording of the ring buffer on panic and
flush the cache of the ring buffer's memory.

Fixes: e645535a ("tracing: Add option to use memmapped memory for trace boot instance")
Cc: stable@vger.kernel.org
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ian Rogers <irogers@google.com>
Link: https://patch.msgid.link/177751969602.2136606.12031934362587643488.stgit@mhiramat.tok.corp.google.com


Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent a254b6d1

arch/alpha/include/asm/Kbuild

+1 −0
Original line number Diff line number Diff line
@@ -5,4 +5,5 @@ generic-y += agp.h 
generic-y += asm-offsets.h

generic-y += kvm_para.h

generic-y += mcs_spinlock.h

generic-y += ring_buffer.h

generic-y += text-patching.h

arch/arc/include/asm/Kbuild

+1 −0
Original line number Diff line number Diff line
@@ -5,5 +5,6 @@ generic-y += extable.h 
generic-y += kvm_para.h

generic-y += mcs_spinlock.h

generic-y += parport.h

generic-y += ring_buffer.h

generic-y += user.h

generic-y += text-patching.h

arch/arm/include/asm/Kbuild

+1 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ generic-y += early_ioremap.h 
generic-y += extable.h

generic-y += flat.h

generic-y += parport.h

generic-y += ring_buffer.h



generated-y += mach-types.h

generated-y += unistd-nr.h

arch/arm64/include/asm/ring_buffer.h

0 → 100644
+10 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

#ifndef _ASM_ARM64_RING_BUFFER_H

#define _ASM_ARM64_RING_BUFFER_H



#include <asm/cacheflush.h>



/* Flush D-cache on persistent ring buffer */

#define arch_ring_buffer_flush_range(start, end)	dcache_clean_pop(start, end)



#endif /* _ASM_ARM64_RING_BUFFER_H */

arch/csky/include/asm/Kbuild

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ generic-y += qrwlock.h 
generic-y += qrwlock_types.h

generic-y += qspinlock.h

generic-y += parport.h

generic-y += ring_buffer.h

generic-y += user.h

generic-y += vmlinux.lds.h

generic-y += text-patching.h