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Diffstat (limited to 'fs/pstore/platform.c')
-rw-r--r--fs/pstore/platform.c75
1 files changed, 52 insertions, 23 deletions
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 62356d542ef6..f8b9c9c73997 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -92,17 +92,24 @@ 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;
+/*
+ * Compression is only used for dmesg output, which consists of low-entropy
+ * ASCII text, and so we can assume worst-case 60%.
+ */
+#define DMESG_COMP_PERCENT 60
+
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 */
@@ -196,6 +203,7 @@ static int pstore_compress(const void *in, void *out,
static void allocate_buf_for_compression(void)
{
+ size_t compressed_size;
char *buf;
/* Skip if not built-in or compression disabled. */
@@ -216,7 +224,8 @@ static void allocate_buf_for_compression(void)
* uncompressed record size, since any record that would be expanded by
* compression is just stored uncompressed.
*/
- buf = kvzalloc(psinfo->bufsize, GFP_KERNEL);
+ compressed_size = (psinfo->bufsize * 100) / DMESG_COMP_PERCENT;
+ buf = kvzalloc(compressed_size, GFP_KERNEL);
if (!buf) {
pr_err("Failed %zu byte compression buffer allocation for: %s\n",
psinfo->bufsize, compress);
@@ -233,6 +242,7 @@ static void allocate_buf_for_compression(void)
/* A non-NULL big_oops_buf indicates compression is available. */
big_oops_buf = buf;
+ max_compressed_size = compressed_size;
pr_info("Using crash dump compression: %s\n", compress);
}
@@ -246,6 +256,7 @@ static void free_buf_for_compression(void)
kvfree(big_oops_buf);
big_oops_buf = NULL;
+ max_compressed_size = 0;
}
void pstore_record_init(struct pstore_record *record,
@@ -264,9 +275,10 @@ 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 int remaining = READ_ONCE(kmsg_bytes);
unsigned long total = 0;
const char *why;
unsigned int part = 1;
@@ -274,22 +286,22 @@ 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 (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
+ if (pstore_cannot_block_path(detail->reason)) {
+ if (!raw_spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
pr_err("dump skipped in %s path because of concurrent dump\n",
in_nmi() ? "NMI" : why);
return;
}
} else {
- spin_lock_irqsave(&psinfo->buf_lock, flags);
+ raw_spin_lock_irqsave(&psinfo->buf_lock, flags);
}
kmsg_dump_rewind(&iter);
oopscount++;
- while (total < kmsg_bytes) {
+ while (total < remaining) {
char *dst;
size_t dst_size;
int header_size;
@@ -300,12 +312,12 @@ 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;
dst = big_oops_buf ?: psinfo->buf;
- dst_size = psinfo->bufsize;
+ dst_size = max_compressed_size ?: psinfo->bufsize;
/* Write dump header. */
header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
@@ -326,15 +338,22 @@ static void pstore_dump(struct kmsg_dumper *dumper,
record.compressed = true;
record.size = zipped_len;
} else {
- record.size = header_size + dump_size;
- memcpy(psinfo->buf, dst, record.size);
+ /*
+ * Compression failed, so the buffer is most
+ * likely filled with binary data that does not
+ * compress as well as ASCII text. Copy as much
+ * of the uncompressed data as possible into
+ * the pstore record, and discard the rest.
+ */
+ record.size = psinfo->bufsize;
+ memcpy(psinfo->buf, dst, psinfo->bufsize);
}
} else {
record.size = header_size + dump_size;
}
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 {
@@ -346,7 +365,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
total += record.size;
part++;
}
- spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+ raw_spin_unlock_irqrestore(&psinfo->buf_lock, flags);
if (saved_ret) {
pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,
@@ -446,6 +465,8 @@ out:
*/
int pstore_register(struct pstore_info *psi)
{
+ char *new_backend;
+
if (backend && strcmp(backend, psi->name)) {
pr_warn("backend '%s' already in use: ignoring '%s'\n",
backend, psi->name);
@@ -466,11 +487,16 @@ int pstore_register(struct pstore_info *psi)
return -EINVAL;
}
+ new_backend = kstrdup(psi->name, GFP_KERNEL);
+ if (!new_backend)
+ return -ENOMEM;
+
mutex_lock(&psinfo_lock);
if (psinfo) {
pr_warn("backend '%s' already loaded: ignoring '%s'\n",
psinfo->name, psi->name);
mutex_unlock(&psinfo_lock);
+ kfree(new_backend);
return -EBUSY;
}
@@ -478,7 +504,7 @@ int pstore_register(struct pstore_info *psi)
psi->write_user = pstore_write_user_compat;
psinfo = psi;
mutex_init(&psinfo->read_mutex);
- spin_lock_init(&psinfo->buf_lock);
+ raw_spin_lock_init(&psinfo->buf_lock);
if (psi->flags & PSTORE_FLAGS_DMESG)
allocate_buf_for_compression();
@@ -503,7 +529,7 @@ int pstore_register(struct pstore_info *psi)
* Update the module parameter backend, so it is visible
* through /sys/module/pstore/parameters/backend
*/
- backend = kstrdup(psi->name, GFP_KERNEL);
+ backend = new_backend;
pr_info("Registered %s as persistent store backend\n", psi->name);
@@ -537,7 +563,7 @@ void pstore_unregister(struct pstore_info *psi)
pstore_unregister_kmsg();
/* Stop timer and make sure all work has finished. */
- del_timer_sync(&pstore_timer);
+ timer_delete_sync(&pstore_timer);
flush_work(&pstore_work);
/* Remove all backend records from filesystem tree. */
@@ -560,6 +586,7 @@ static void decompress_record(struct pstore_record *record,
int ret;
int unzipped_len;
char *unzipped, *workspace;
+ size_t max_uncompressed_size;
if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
return;
@@ -583,7 +610,8 @@ static void decompress_record(struct pstore_record *record,
}
/* Allocate enough space to hold max decompression and ECC. */
- workspace = kvzalloc(psinfo->bufsize + record->ecc_notice_size,
+ max_uncompressed_size = 3 * psinfo->bufsize;
+ workspace = kvzalloc(max_uncompressed_size + record->ecc_notice_size,
GFP_KERNEL);
if (!workspace)
return;
@@ -591,11 +619,11 @@ static void decompress_record(struct pstore_record *record,
zstream->next_in = record->buf;
zstream->avail_in = record->size;
zstream->next_out = workspace;
- zstream->avail_out = psinfo->bufsize;
+ zstream->avail_out = max_uncompressed_size;
ret = zlib_inflate(zstream, Z_FINISH);
if (ret != Z_STREAM_END) {
- pr_err("zlib_inflate() failed, ret = %d!\n", ret);
+ pr_err_ratelimited("zlib_inflate() failed, ret = %d!\n", ret);
kvfree(workspace);
return;
}
@@ -734,4 +762,5 @@ static void __exit pstore_exit(void)
module_exit(pstore_exit)
MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
+MODULE_DESCRIPTION("Persistent Storage - platform driver interface");
MODULE_LICENSE("GPL");
generated by cgit (git 2.34.1) at 2025-12-24 19:46:21 +0000