From e1a261ba599eec97e1c5c7760d5c3698fc24e6a6 Mon Sep 17 00:00:00 2001 From: Jocelyn Falempe Date: Tue, 2 Jul 2024 14:26:04 +0200 Subject: [PATCH] printk: Add a short description string to kmsg_dump() kmsg_dump doesn't forward the panic reason string to the kmsg_dumper callback. This patch adds a new struct kmsg_dump_detail, that will hold the reason and description, and pass it to the dump() callback. To avoid updating all kmsg_dump() call, it adds a kmsg_dump_desc() function and a macro for backward compatibility. I've written this for drm_panic, but it can be useful for other kmsg_dumper. It allows to see the panic reason, like "sysrq triggered crash" or "VFS: Unable to mount root fs on xxxx" on the drm panic screen. v2: * Use a struct kmsg_dump_detail to hold the reason and description pointer, for more flexibility if we want to add other parameters. (Kees Cook) * Fix powerpc/nvram_64 build, as I didn't update the forward declaration of oops_to_nvram() Signed-off-by: Jocelyn Falempe Acked-by: Petr Mladek Acked-by: Michael Ellerman (powerpc) Acked-by: Kees Cook Link: https://patchwork.freedesktop.org/patch/msgid/20240702122639.248110-1-jfalempe@redhat.com --- arch/powerpc/kernel/nvram_64.c | 8 ++++---- arch/powerpc/platforms/powernv/opal-kmsg.c | 4 ++-- arch/um/kernel/kmsg_dump.c | 2 +- drivers/gpu/drm/drm_panic.c | 4 ++-- drivers/hv/hv_common.c | 4 ++-- drivers/mtd/mtdoops.c | 2 +- fs/pstore/platform.c | 10 +++++----- include/linux/kmsg_dump.h | 22 +++++++++++++++++++--- kernel/panic.c | 2 +- kernel/printk/printk.c | 11 ++++++++--- 10 files changed, 45 insertions(+), 24 deletions(-) diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c index e385d3164648..f9c6568a9137 100644 --- a/arch/powerpc/kernel/nvram_64.c +++ b/arch/powerpc/kernel/nvram_64.c @@ -73,7 +73,7 @@ static const char *nvram_os_partitions[] = { }; static void oops_to_nvram(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason); + struct kmsg_dump_detail *detail); static struct kmsg_dumper nvram_kmsg_dumper = { .dump = oops_to_nvram @@ -643,7 +643,7 @@ void __init nvram_init_oops_partition(int rtas_partition_exists) * partition. If that's too much, go back and capture uncompressed text. */ static void oops_to_nvram(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason) + struct kmsg_dump_detail *detail) { struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf; static unsigned int oops_count = 0; @@ -655,7 +655,7 @@ static void oops_to_nvram(struct kmsg_dumper *dumper, unsigned int err_type = ERR_TYPE_KERNEL_PANIC_GZ; int rc = -1; - switch (reason) { + switch (detail->reason) { case KMSG_DUMP_SHUTDOWN: /* These are almost always orderly shutdowns. */ return; @@ -671,7 +671,7 @@ static void oops_to_nvram(struct kmsg_dumper *dumper, break; default: pr_err("%s: ignoring unrecognized KMSG_DUMP_* reason %d\n", - __func__, (int) reason); + __func__, (int) detail->reason); return; } diff --git a/arch/powerpc/platforms/powernv/opal-kmsg.c b/arch/powerpc/platforms/powernv/opal-kmsg.c index 6c3bc4b4da98..bb4218fa796e 100644 --- a/arch/powerpc/platforms/powernv/opal-kmsg.c +++ b/arch/powerpc/platforms/powernv/opal-kmsg.c @@ -20,13 +20,13 @@ * message, it just ensures that OPAL completely flushes the console buffer. */ static void kmsg_dump_opal_console_flush(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason) + struct kmsg_dump_detail *detail) { /* * Outside of a panic context the pollers will continue to run, * so we don't need to do any special flushing. */ - if (reason != KMSG_DUMP_PANIC) + if (detail->reason != KMSG_DUMP_PANIC) return; opal_flush_console(0); diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c index 4382cf02a6d1..419021175272 100644 --- a/arch/um/kernel/kmsg_dump.c +++ b/arch/um/kernel/kmsg_dump.c @@ -8,7 +8,7 @@ #include static void kmsg_dumper_stdout(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason) + struct kmsg_dump_detail *detail) { static struct kmsg_dump_iter iter; static DEFINE_SPINLOCK(lock); diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index 948aed00595e..8794c7f6c0ee 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -655,11 +655,11 @@ static struct drm_plane *to_drm_plane(struct kmsg_dumper *kd) return container_of(kd, struct drm_plane, kmsg_panic); } -static void drm_panic(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason) +static void drm_panic(struct kmsg_dumper *dumper, struct kmsg_dump_detail *detail) { struct drm_plane *plane = to_drm_plane(dumper); - if (reason == KMSG_DUMP_PANIC) + if (detail->reason == KMSG_DUMP_PANIC) draw_panic_plane(plane); } diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 9c452bfbd571..7a35c82976e0 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -207,13 +207,13 @@ static int hv_die_panic_notify_crash(struct notifier_block *self, * buffer and call into Hyper-V to transfer the data. */ static void hv_kmsg_dump(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason) + struct kmsg_dump_detail *detail) { struct kmsg_dump_iter iter; size_t bytes_written; /* We are only interested in panics. */ - if (reason != KMSG_DUMP_PANIC || !sysctl_record_panic_msg) + if (detail->reason != KMSG_DUMP_PANIC || !sysctl_record_panic_msg) return; /* diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 2f11585b5613..86d49db9196d 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -298,7 +298,7 @@ static void find_next_position(struct mtdoops_context *cxt) } static void mtdoops_do_dump(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason) + struct kmsg_dump_detail *detail) { struct mtdoops_context *cxt = container_of(dumper, struct mtdoops_context, dump); diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 03425928d2fb..7f5810589a26 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -275,7 +275,7 @@ void pstore_record_init(struct pstore_record *record, * end of the buffer. */ static void pstore_dump(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason) + struct kmsg_dump_detail *detail) { struct kmsg_dump_iter iter; unsigned long total = 0; @@ -285,9 +285,9 @@ static void pstore_dump(struct kmsg_dumper *dumper, int saved_ret = 0; int ret; - why = kmsg_dump_reason_str(reason); + why = kmsg_dump_reason_str(detail->reason); - if (pstore_cannot_block_path(reason)) { + if (pstore_cannot_block_path(detail->reason)) { if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) { pr_err("dump skipped in %s path because of concurrent dump\n", in_nmi() ? "NMI" : why); @@ -311,7 +311,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, pstore_record_init(&record, psinfo); record.type = PSTORE_TYPE_DMESG; record.count = oopscount; - record.reason = reason; + record.reason = detail->reason; record.part = part; record.buf = psinfo->buf; @@ -352,7 +352,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, } ret = psinfo->write(&record); - if (ret == 0 && reason == KMSG_DUMP_OOPS) { + if (ret == 0 && detail->reason == KMSG_DUMP_OOPS) { pstore_new_entry = 1; pstore_timer_kick(); } else { diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 906521c2329c..6055fc969877 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -39,6 +39,17 @@ struct kmsg_dump_iter { u64 next_seq; }; +/** + * struct kmsg_dump_detail - kernel crash detail + * @reason: reason for the crash, see kmsg_dump_reason. + * @description: optional short string, to provide additional information. + */ + +struct kmsg_dump_detail { + enum kmsg_dump_reason reason; + const char *description; +}; + /** * struct kmsg_dumper - kernel crash message dumper structure * @list: Entry in the dumper list (private) @@ -49,13 +60,13 @@ struct kmsg_dump_iter { */ struct kmsg_dumper { struct list_head list; - void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason); + void (*dump)(struct kmsg_dumper *dumper, struct kmsg_dump_detail *detail); enum kmsg_dump_reason max_reason; bool registered; }; #ifdef CONFIG_PRINTK -void kmsg_dump(enum kmsg_dump_reason reason); +void kmsg_dump_desc(enum kmsg_dump_reason reason, const char *desc); bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, char *line, size_t size, size_t *len); @@ -71,7 +82,7 @@ int kmsg_dump_unregister(struct kmsg_dumper *dumper); const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason); #else -static inline void kmsg_dump(enum kmsg_dump_reason reason) +static inline void kmsg_dump_desc(enum kmsg_dump_reason reason, const char *desc) { } @@ -107,4 +118,9 @@ static inline const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason) } #endif +static inline void kmsg_dump(enum kmsg_dump_reason reason) +{ + kmsg_dump_desc(reason, NULL); +} + #endif /* _LINUX_KMSG_DUMP_H */ diff --git a/kernel/panic.c b/kernel/panic.c index 8bff183d6180..d6219841f491 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -375,7 +375,7 @@ void panic(const char *fmt, ...) panic_print_sys_info(false); - kmsg_dump(KMSG_DUMP_PANIC); + kmsg_dump_desc(KMSG_DUMP_PANIC, buf); /* * If you doubt kdump always works fine in any situation, diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 420fd310129d..4310ff3f23e5 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -4126,16 +4126,21 @@ const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason) EXPORT_SYMBOL_GPL(kmsg_dump_reason_str); /** - * kmsg_dump - dump kernel log to kernel message dumpers. + * kmsg_dump_desc - dump kernel log to kernel message dumpers. * @reason: the reason (oops, panic etc) for dumping + * @desc: a short string to describe what caused the panic or oops. Can be NULL + * if no additional description is available. * * Call each of the registered dumper's dump() callback, which can * retrieve the kmsg records with kmsg_dump_get_line() or * kmsg_dump_get_buffer(). */ -void kmsg_dump(enum kmsg_dump_reason reason) +void kmsg_dump_desc(enum kmsg_dump_reason reason, const char *desc) { struct kmsg_dumper *dumper; + struct kmsg_dump_detail detail = { + .reason = reason, + .description = desc}; rcu_read_lock(); list_for_each_entry_rcu(dumper, &dump_list, list) { @@ -4153,7 +4158,7 @@ void kmsg_dump(enum kmsg_dump_reason reason) continue; /* invoke dumper which will iterate over records */ - dumper->dump(dumper, reason); + dumper->dump(dumper, &detail); } rcu_read_unlock(); }