From: Masami Hiramatsu (Google) Date: Thu, 30 Apr 2026 03:28:16 +0000 (+0900) Subject: ring-buffer: Flush and stop persistent ring buffer on panic X-Git-Tag: v7.1-rc5~42^2~3 X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=a494d3c8d5392bcdff83c2a593df0c160ff9f322;p=thirdparty%2Flinux.git 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: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") Cc: stable@vger.kernel.org Cc: Will Deacon Cc: Mathieu Desnoyers Cc: Ian Rogers Link: https://patch.msgid.link/177751969602.2136606.12031934362587643488.stgit@mhiramat.tok.corp.google.com Signed-off-by: Masami Hiramatsu (Google) Acked-by: Catalin Marinas Acked-by: Geert Uytterhoeven Signed-off-by: Steven Rostedt --- diff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild index 483965c5a4de2..b154b4e3dfa86 100644 --- a/arch/alpha/include/asm/Kbuild +++ b/arch/alpha/include/asm/Kbuild @@ -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 diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild index 4c69522e0328e..483caacc69884 100644 --- a/arch/arc/include/asm/Kbuild +++ b/arch/arc/include/asm/Kbuild @@ -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 diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild index 03657ff8fbe3d..decad5f2c826f 100644 --- a/arch/arm/include/asm/Kbuild +++ b/arch/arm/include/asm/Kbuild @@ -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 diff --git a/arch/arm64/include/asm/ring_buffer.h b/arch/arm64/include/asm/ring_buffer.h new file mode 100644 index 0000000000000..62316c4068881 --- /dev/null +++ b/arch/arm64/include/asm/ring_buffer.h @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _ASM_ARM64_RING_BUFFER_H +#define _ASM_ARM64_RING_BUFFER_H + +#include + +/* 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 */ diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild index 3a5c7f6e5aacb..7dca0c6cdc848 100644 --- a/arch/csky/include/asm/Kbuild +++ b/arch/csky/include/asm/Kbuild @@ -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 diff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild index 1efa1e993d4b9..0f887d4238edd 100644 --- a/arch/hexagon/include/asm/Kbuild +++ b/arch/hexagon/include/asm/Kbuild @@ -5,4 +5,5 @@ generic-y += extable.h generic-y += iomap.h generic-y += kvm_para.h generic-y += mcs_spinlock.h +generic-y += ring_buffer.h generic-y += text-patching.h diff --git a/arch/loongarch/include/asm/Kbuild b/arch/loongarch/include/asm/Kbuild index 9034b583a88a6..7e92957baf6a0 100644 --- a/arch/loongarch/include/asm/Kbuild +++ b/arch/loongarch/include/asm/Kbuild @@ -10,5 +10,6 @@ generic-y += qrwlock.h generic-y += user.h generic-y += ioctl.h generic-y += mmzone.h +generic-y += ring_buffer.h generic-y += statfs.h generic-y += text-patching.h diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild index b282e0dd8dc10..62543bf305ff1 100644 --- a/arch/m68k/include/asm/Kbuild +++ b/arch/m68k/include/asm/Kbuild @@ -3,5 +3,6 @@ generated-y += syscall_table.h generic-y += extable.h generic-y += kvm_para.h generic-y += mcs_spinlock.h +generic-y += ring_buffer.h generic-y += spinlock.h generic-y += text-patching.h diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild index 7178f990e8b3d..0030309b47ad8 100644 --- a/arch/microblaze/include/asm/Kbuild +++ b/arch/microblaze/include/asm/Kbuild @@ -5,6 +5,7 @@ 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 += syscalls.h generic-y += tlb.h generic-y += user.h diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild index 684569b2ecd6b..9771c3d85074c 100644 --- a/arch/mips/include/asm/Kbuild +++ b/arch/mips/include/asm/Kbuild @@ -12,5 +12,6 @@ generic-y += mcs_spinlock.h generic-y += parport.h generic-y += qrwlock.h generic-y += qspinlock.h +generic-y += ring_buffer.h generic-y += user.h generic-y += text-patching.h diff --git a/arch/nios2/include/asm/Kbuild b/arch/nios2/include/asm/Kbuild index 28004301c236f..0a25309644133 100644 --- a/arch/nios2/include/asm/Kbuild +++ b/arch/nios2/include/asm/Kbuild @@ -5,6 +5,7 @@ generic-y += cmpxchg.h generic-y += extable.h generic-y += kvm_para.h generic-y += mcs_spinlock.h +generic-y += ring_buffer.h generic-y += spinlock.h generic-y += user.h generic-y += text-patching.h diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild index cef49d60d74c0..8aa34621702de 100644 --- a/arch/openrisc/include/asm/Kbuild +++ b/arch/openrisc/include/asm/Kbuild @@ -8,4 +8,5 @@ generic-y += spinlock_types.h generic-y += spinlock.h generic-y += qrwlock_types.h generic-y += qrwlock.h +generic-y += ring_buffer.h generic-y += user.h diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild index 4fb596d94c893..d48d158f72412 100644 --- a/arch/parisc/include/asm/Kbuild +++ b/arch/parisc/include/asm/Kbuild @@ -4,4 +4,5 @@ generated-y += syscall_table_64.h generic-y += agp.h generic-y += kvm_para.h generic-y += mcs_spinlock.h +generic-y += ring_buffer.h generic-y += user.h diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild index 2e23533b67e30..805b5aeebb6f3 100644 --- a/arch/powerpc/include/asm/Kbuild +++ b/arch/powerpc/include/asm/Kbuild @@ -5,4 +5,5 @@ generated-y += syscall_table_spu.h generic-y += agp.h generic-y += mcs_spinlock.h generic-y += qrwlock.h +generic-y += ring_buffer.h generic-y += early_ioremap.h diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild index bd5fc94032953..7721b63642f41 100644 --- a/arch/riscv/include/asm/Kbuild +++ b/arch/riscv/include/asm/Kbuild @@ -14,5 +14,6 @@ generic-y += ticket_spinlock.h generic-y += qrwlock.h generic-y += qrwlock_types.h generic-y += qspinlock.h +generic-y += ring_buffer.h generic-y += user.h generic-y += vmlinux.lds.h diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild index 80bad7de7a04a..0c1fc47c3ba0a 100644 --- a/arch/s390/include/asm/Kbuild +++ b/arch/s390/include/asm/Kbuild @@ -7,3 +7,4 @@ generated-y += unistd_nr.h generic-y += asm-offsets.h generic-y += mcs_spinlock.h generic-y += mmzone.h +generic-y += ring_buffer.h diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild index 4d3f10ed82758..f0403d3ee8ab8 100644 --- a/arch/sh/include/asm/Kbuild +++ b/arch/sh/include/asm/Kbuild @@ -3,4 +3,5 @@ generated-y += syscall_table.h generic-y += kvm_para.h generic-y += mcs_spinlock.h generic-y += parport.h +generic-y += ring_buffer.h generic-y += text-patching.h diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild index 17ee8a273aa6b..49c6bb326b75b 100644 --- a/arch/sparc/include/asm/Kbuild +++ b/arch/sparc/include/asm/Kbuild @@ -4,4 +4,5 @@ generated-y += syscall_table_64.h generic-y += agp.h generic-y += kvm_para.h generic-y += mcs_spinlock.h +generic-y += ring_buffer.h generic-y += text-patching.h diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild index 1b9b82bbe3220..2a1629ba81404 100644 --- a/arch/um/include/asm/Kbuild +++ b/arch/um/include/asm/Kbuild @@ -17,6 +17,7 @@ generic-y += module.lds.h generic-y += parport.h generic-y += percpu.h generic-y += preempt.h +generic-y += ring_buffer.h generic-y += runtime-const.h generic-y += softirq_stack.h generic-y += switch_to.h diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild index 4566000e15c44..078fd2c0d69df 100644 --- a/arch/x86/include/asm/Kbuild +++ b/arch/x86/include/asm/Kbuild @@ -14,3 +14,4 @@ generic-y += early_ioremap.h generic-y += fprobe.h generic-y += mcs_spinlock.h generic-y += mmzone.h +generic-y += ring_buffer.h diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild index 13fe45dea2961..e57af619263a1 100644 --- a/arch/xtensa/include/asm/Kbuild +++ b/arch/xtensa/include/asm/Kbuild @@ -6,5 +6,6 @@ generic-y += mcs_spinlock.h generic-y += parport.h generic-y += qrwlock.h generic-y += qspinlock.h +generic-y += ring_buffer.h generic-y += user.h generic-y += text-patching.h diff --git a/include/asm-generic/ring_buffer.h b/include/asm-generic/ring_buffer.h new file mode 100644 index 0000000000000..201d2aee10054 --- /dev/null +++ b/include/asm-generic/ring_buffer.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Generic arch dependent ring_buffer macros. + */ +#ifndef __ASM_GENERIC_RING_BUFFER_H__ +#define __ASM_GENERIC_RING_BUFFER_H__ + +#include + +/* Flush cache on ring buffer range if needed. Do nothing by default. */ +#define arch_ring_buffer_flush_range(start, end) do { } while (0) + +#endif /* __ASM_GENERIC_RING_BUFFER_H__ */ diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index fcd93d49851ec..7b07d2004cc6f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -31,6 +32,7 @@ #include #include +#include #include #include #include @@ -559,6 +561,7 @@ struct trace_buffer { unsigned long range_addr_start; unsigned long range_addr_end; + struct notifier_block flush_nb; struct ring_buffer_meta *meta; @@ -2521,6 +2524,16 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer) kfree(cpu_buffer); } +/* Stop recording on a persistent buffer and flush cache if needed. */ +static int rb_flush_buffer_cb(struct notifier_block *nb, unsigned long event, void *data) +{ + struct trace_buffer *buffer = container_of(nb, struct trace_buffer, flush_nb); + + ring_buffer_record_off(buffer); + arch_ring_buffer_flush_range(buffer->range_addr_start, buffer->range_addr_end); + return NOTIFY_DONE; +} + static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, int order, unsigned long start, unsigned long end, @@ -2651,6 +2664,12 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, mutex_init(&buffer->mutex); + /* Persistent ring buffer needs to flush cache before reboot. */ + if (start && end) { + buffer->flush_nb.notifier_call = rb_flush_buffer_cb; + atomic_notifier_chain_register(&panic_notifier_list, &buffer->flush_nb); + } + return_ptr(buffer); fail_free_buffers: @@ -2749,6 +2768,9 @@ ring_buffer_free(struct trace_buffer *buffer) { int cpu; + if (buffer->range_addr_start && buffer->range_addr_end) + atomic_notifier_chain_unregister(&panic_notifier_list, &buffer->flush_nb); + cpuhp_state_remove_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node); irq_work_sync(&buffer->irq_work.work);