From: Kees Cook kees@kernel.org
[ Upstream commit 5674609535bafa834ab014d90d9bbe8e89223a0b ]
The types around kmsg_bytes were inconsistent. The global was unsigned long, the argument to pstore_set_kmsg_bytes() was int, and the filesystem option was u32. Given other internal limits, there's not much sense in making a single pstore record larger than INT_MAX and it can't be negative, so use u32 everywhere. Additionally, use READ/WRITE_ONCE and a local variable in pstore_dump() to avoid kmsg_bytes changing during a dump.
Link: https://lore.kernel.org/r/20250206191655.work.798-kees@kernel.org Signed-off-by: Kees Cook kees@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/pstore/inode.c | 2 +- fs/pstore/internal.h | 4 ++-- fs/pstore/platform.c | 11 ++++++----- 3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index 7dbbf3b6d98d3..a1c97cd2720a6 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -264,7 +264,7 @@ static void parse_options(char *options) static int pstore_show_options(struct seq_file *m, struct dentry *root) { if (kmsg_bytes != CONFIG_PSTORE_DEFAULT_KMSG_BYTES) - seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes); + seq_printf(m, ",kmsg_bytes=%u", kmsg_bytes); return 0; }
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h index 801d6c0b170c3..a0fc511969100 100644 --- a/fs/pstore/internal.h +++ b/fs/pstore/internal.h @@ -6,7 +6,7 @@ #include <linux/time.h> #include <linux/pstore.h>
-extern unsigned long kmsg_bytes; +extern unsigned int kmsg_bytes;
#ifdef CONFIG_PSTORE_FTRACE extern void pstore_register_ftrace(void); @@ -35,7 +35,7 @@ static inline void pstore_unregister_pmsg(void) {}
extern struct pstore_info *psinfo;
-extern void pstore_set_kmsg_bytes(int); +extern void pstore_set_kmsg_bytes(unsigned int bytes); extern void pstore_get_records(int); extern void pstore_get_backend_records(struct pstore_info *psi, struct dentry *root, int quiet); diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 03425928d2fb3..ef62389212b60 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -92,8 +92,8 @@ module_param(compress, charp, 0444); MODULE_PARM_DESC(compress, "compression to use");
/* How much of the kernel log to snapshot */ -unsigned long kmsg_bytes = CONFIG_PSTORE_DEFAULT_KMSG_BYTES; -module_param(kmsg_bytes, ulong, 0444); +unsigned int kmsg_bytes = CONFIG_PSTORE_DEFAULT_KMSG_BYTES; +module_param(kmsg_bytes, uint, 0444); MODULE_PARM_DESC(kmsg_bytes, "amount of kernel log to snapshot (in bytes)");
static void *compress_workspace; @@ -107,9 +107,9 @@ static void *compress_workspace; static char *big_oops_buf; static size_t max_compressed_size;
-void pstore_set_kmsg_bytes(int bytes) +void pstore_set_kmsg_bytes(unsigned int bytes) { - kmsg_bytes = bytes; + WRITE_ONCE(kmsg_bytes, bytes); }
/* Tag each group of saved records with a sequence number */ @@ -278,6 +278,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason) { struct kmsg_dump_iter iter; + unsigned int remaining = READ_ONCE(kmsg_bytes); unsigned long total = 0; const char *why; unsigned int part = 1; @@ -300,7 +301,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, kmsg_dump_rewind(&iter);
oopscount++; - while (total < kmsg_bytes) { + while (total < remaining) { char *dst; size_t dst_size; int header_size;