[PATCH] printk: Add a short description string to kmsg_dump()
Jocelyn Falempe
jfalempe at redhat.com
Tue Jun 25 22:39:29 AEST 2024
kmsg_dump doesn't forward the panic reason string to the kmsg_dumper
callback.
This patch adds a new parameter "const char *desc" to the kmsg_dumper
dump() callback, and update all drivers that are using it.
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.
Signed-off-by: Jocelyn Falempe <jfalempe at redhat.com>
---
arch/powerpc/kernel/nvram_64.c | 3 ++-
arch/powerpc/platforms/powernv/opal-kmsg.c | 3 ++-
drivers/gpu/drm/drm_panic.c | 3 ++-
drivers/hv/hv_common.c | 3 ++-
drivers/mtd/mtdoops.c | 3 ++-
fs/pstore/platform.c | 3 ++-
include/linux/kmsg_dump.h | 13 ++++++++++---
kernel/panic.c | 2 +-
kernel/printk/printk.c | 8 +++++---
9 files changed, 28 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
index e385d3164648c..6b3a80d8cfa64 100644
--- a/arch/powerpc/kernel/nvram_64.c
+++ b/arch/powerpc/kernel/nvram_64.c
@@ -643,7 +643,8 @@ 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)
+ enum kmsg_dump_reason reason,
+ const char *desc)
{
struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
static unsigned int oops_count = 0;
diff --git a/arch/powerpc/platforms/powernv/opal-kmsg.c b/arch/powerpc/platforms/powernv/opal-kmsg.c
index 6c3bc4b4da983..49b60de6feb04 100644
--- a/arch/powerpc/platforms/powernv/opal-kmsg.c
+++ b/arch/powerpc/platforms/powernv/opal-kmsg.c
@@ -20,7 +20,8 @@
* 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)
+ enum kmsg_dump_reason reason,
+ const char *desc)
{
/*
* Outside of a panic context the pollers will continue to run,
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index 293d4dcbc80da..88e9359fe6d78 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -604,7 +604,8 @@ 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, enum kmsg_dump_reason reason,
+ const char *desc)
{
struct drm_plane *plane = to_drm_plane(dumper);
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 9c452bfbd5719..b0786ee9c94e3 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -207,7 +207,8 @@ 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)
+ enum kmsg_dump_reason reason,
+ const char *desc)
{
struct kmsg_dump_iter iter;
size_t bytes_written;
diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index 2f11585b5613e..c618999a96832 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -298,7 +298,8 @@ static void find_next_position(struct mtdoops_context *cxt)
}
static void mtdoops_do_dump(struct kmsg_dumper *dumper,
- enum kmsg_dump_reason reason)
+ enum kmsg_dump_reason reason,
+ const char *desc)
{
struct mtdoops_context *cxt = container_of(dumper,
struct mtdoops_context, dump);
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 3497ede88aa01..a6ed5d56021ef 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -275,7 +275,8 @@ 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)
+ enum kmsg_dump_reason reason,
+ const char *desc)
{
struct kmsg_dump_iter iter;
unsigned long total = 0;
diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 906521c2329ca..a8f8a6204542d 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -49,13 +49,15 @@ 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,
+ enum kmsg_dump_reason reason,
+ const char *desc);
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 +73,7 @@ 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 +109,9 @@ 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 0843a275531a7..0a8b29c44f3c1 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -378,7 +378,7 @@ 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 d0bff0b0abfdb..2e7195894e41a 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -4287,14 +4287,16 @@ 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;
@@ -4314,7 +4316,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
continue;
/* invoke dumper which will iterate over records */
- dumper->dump(dumper, reason);
+ dumper->dump(dumper, reason, desc);
}
rcu_read_unlock();
}
base-commit: f76698bd9a8ca01d3581236082d786e9a6b72bb7
--
2.45.1
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