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authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-05-26 17:07:49 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-06-14 03:52:39 +0400
commit201e4aca5aa179e6c69a4dcd36a3562e56b8d670 (patch)
tree0d75a50b12cd1c8e39119419ed7c65195b518a16
parent33735a94afdfb39c550b952a40f77c60afdddfa5 (diff)
downloadlinux-201e4aca5aa179e6c69a4dcd36a3562e56b8d670.tar.xz
pstore/ram: Should update old dmesg buffer before reading
Without the update, we'll only see the new dmesg buffer after the reboot, but previously we could see it right away. Making an oops visible in pstore filesystem before reboot is a somewhat dubious feature, but removing it wasn't an intentional change, so let's restore it. For this we have to make persistent_ram_save_old() safe for calling multiple times, and also extern it. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/pstore/ram.c2
-rw-r--r--fs/pstore/ram_core.c15
-rw-r--r--include/linux/pstore_ram.h1
3 files changed, 11 insertions, 7 deletions
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 9123cce28c1e..16ff7332eae0 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -106,6 +106,8 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
time->tv_sec = 0;
time->tv_nsec = 0;
+ /* Update old/shadowed buffer. */
+ persistent_ram_save_old(prz);
size = persistent_ram_old_size(prz);
*buf = kmalloc(size, GFP_KERNEL);
if (*buf == NULL)
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 31f8d184f3a0..235513c46aaf 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -250,23 +250,24 @@ static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
persistent_ram_update_ecc(prz, start, count);
}
-static void __init
-persistent_ram_save_old(struct persistent_ram_zone *prz)
+void persistent_ram_save_old(struct persistent_ram_zone *prz)
{
struct persistent_ram_buffer *buffer = prz->buffer;
size_t size = buffer_size(prz);
size_t start = buffer_start(prz);
- char *dest;
- persistent_ram_ecc_old(prz);
+ if (!size)
+ return;
- dest = kmalloc(size, GFP_KERNEL);
- if (dest == NULL) {
+ if (!prz->old_log) {
+ persistent_ram_ecc_old(prz);
+ prz->old_log = kmalloc(size, GFP_KERNEL);
+ }
+ if (!prz->old_log) {
pr_err("persistent_ram: failed to allocate buffer\n");
return;
}
- prz->old_log = dest;
prz->old_log_size = size;
memcpy(prz->old_log, &buffer->data[start], size - start);
memcpy(prz->old_log + size - start, &buffer->data[0], start);
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index 7ed7fd4dba49..4491e8ff36e6 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -75,6 +75,7 @@ struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev,
int persistent_ram_write(struct persistent_ram_zone *prz, const void *s,
unsigned int count);
+void persistent_ram_save_old(struct persistent_ram_zone *prz);
size_t persistent_ram_old_size(struct persistent_ram_zone *prz);
void *persistent_ram_old(struct persistent_ram_zone *prz);
void persistent_ram_free_old(struct persistent_ram_zone *prz);