[PATCH] pstore/ram: verify ramoops header before saving record
On some devices the persistent memory contains junk after a cold boot,
and /dev/pstore/dmesg-ramoops-* are created with random data which is
not the result of a kernel crash.
This patch adds a ramoops header check and skips any
persistent_ram_zone that does not have a valid header.
Signed-off-by: Ben Zhang
---
fs/pstore/ram.c | 40
1 file changed, 28 insertions(+), 12 deletions(-)
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 44a549b..e16af43 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -186,12 +186,34 @@ static ssize_t ramoops_pstore_read(u64 *id, enum
pstore_type_id *type,
ssize_t size;
ssize_t ecc_notice_size;
struct ramoops_context *cxt = psi->data;
- struct persistent_ram_zone *prz;
- int header_length;
+ struct persistent_ram_zone *prz = NULL;
+ int header_length = 0;
+
+ /* Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
+* PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
+* valid time stamps, so it is initialized to zero.
+*/
+ time->tv_sec = 0;
+ time->tv_nsec = 0;
+ *compressed = false;
+
+ /* Find the next valid persistent_ram_zone for DMESG */
+ while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
+ prz = ramoops_get_next_prz(cxt->przs, >dump_read_cnt,
+ cxt->max_dump_cnt, id, type,
+ PSTORE_TYPE_DMESG, 1);
+ if (!prz_ok(prz))
+ continue;
+ header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
+ time, compressed);
+ /* Clear and skip this DMESG record if it has no valid header */
+ if (!header_length) {
+ persistent_ram_free_old(prz);
+ persistent_ram_zap(prz);
+ prz = NULL;
+ }
+ }
- prz = ramoops_get_next_prz(cxt->przs, >dump_read_cnt,
- cxt->max_dump_cnt, id, type,
- PSTORE_TYPE_DMESG, 1);
if (!prz_ok(prz))
prz = ramoops_get_next_prz(>cprz, >console_read_cnt,
1, id, type, PSTORE_TYPE_CONSOLE, 0);
@@ -204,13 +226,7 @@ static ssize_t ramoops_pstore_read(u64 *id, enum
pstore_type_id *type,
if (!prz_ok(prz))
return 0;
- if (!persistent_ram_old(prz))
- return 0;
-
- size = persistent_ram_old_size(prz);
- header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz), time,
- compressed);
- size -= header_length;
+ size = persistent_ram_old_size(prz) - header_length;
/* ECC correction notice */
ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
--
2.2.0.rc0.207.ga3a616c
--
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[PATCH] pstore/ram: verify ramoops header before saving record
On some devices the persistent memory contains junk after a cold boot,
and /dev/pstore/dmesg-ramoops-* are created with random data which is
not the result of a kernel crash.
This patch adds a ramoops header check and skips any
persistent_ram_zone that does not have a valid header.
Signed-off-by: Ben Zhang be...@chromium.org
---
fs/pstore/ram.c | 40
1 file changed, 28 insertions(+), 12 deletions(-)
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 44a549b..e16af43 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -186,12 +186,34 @@ static ssize_t ramoops_pstore_read(u64 *id, enum
pstore_type_id *type,
ssize_t size;
ssize_t ecc_notice_size;
struct ramoops_context *cxt = psi-data;
- struct persistent_ram_zone *prz;
- int header_length;
+ struct persistent_ram_zone *prz = NULL;
+ int header_length = 0;
+
+ /* Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
+* PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
+* valid time stamps, so it is initialized to zero.
+*/
+ time-tv_sec = 0;
+ time-tv_nsec = 0;
+ *compressed = false;
+
+ /* Find the next valid persistent_ram_zone for DMESG */
+ while (cxt-dump_read_cnt cxt-max_dump_cnt !prz) {
+ prz = ramoops_get_next_prz(cxt-przs, cxt-dump_read_cnt,
+ cxt-max_dump_cnt, id, type,
+ PSTORE_TYPE_DMESG, 1);
+ if (!prz_ok(prz))
+ continue;
+ header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
+ time, compressed);
+ /* Clear and skip this DMESG record if it has no valid header */
+ if (!header_length) {
+ persistent_ram_free_old(prz);
+ persistent_ram_zap(prz);
+ prz = NULL;
+ }
+ }
- prz = ramoops_get_next_prz(cxt-przs, cxt-dump_read_cnt,
- cxt-max_dump_cnt, id, type,
- PSTORE_TYPE_DMESG, 1);
if (!prz_ok(prz))
prz = ramoops_get_next_prz(cxt-cprz, cxt-console_read_cnt,
1, id, type, PSTORE_TYPE_CONSOLE, 0);
@@ -204,13 +226,7 @@ static ssize_t ramoops_pstore_read(u64 *id, enum
pstore_type_id *type,
if (!prz_ok(prz))
return 0;
- if (!persistent_ram_old(prz))
- return 0;
-
- size = persistent_ram_old_size(prz);
- header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz), time,
- compressed);
- size -= header_length;
+ size = persistent_ram_old_size(prz) - header_length;
/* ECC correction notice */
ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
--
2.2.0.rc0.207.ga3a616c
--
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