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pstore: Merge per-CPU ftrace records into one

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Up until this patch, each of the per CPU ftrace buffers appear as a
separate ftrace-ramoops-N file. In this patch we merge all the zones into
one and populate a single ftrace-ramoops-0 file.

Signed-off-by: Joel Fernandes <joelaf@google.com>
[kees: clarified variables names, added -ENOMEM handling]
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Joel Fernandes 2016-10-20 00:34:06 -07:00 committed by Kees Cook
parent fbccdeb8d7
commit 2fbea82bbb
1 changed files with 111 additions and 15 deletions
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126
fs/pstore/ram.c
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@ -182,16 +182,69 @@ static bool prz_ok(struct persistent_ram_zone *prz)
persistent_ram_ecc_string(prz, NULL, 0));
}
static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest,
struct persistent_ram_zone *src)
{
size_t dest_size, src_size, total, dest_off, src_off;
size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
void *merged_buf;
struct pstore_ftrace_record *drec, *srec, *mrec;
size_t record_size = sizeof(struct pstore_ftrace_record);
dest_off = dest->old_log_size % record_size;
dest_size = dest->old_log_size - dest_off;
src_off = src->old_log_size % record_size;
src_size = src->old_log_size - src_off;
total = dest_size + src_size;
merged_buf = kmalloc(total, GFP_KERNEL);
if (!merged_buf)
return -ENOMEM;
drec = (struct pstore_ftrace_record *)(dest->old_log + dest_off);
srec = (struct pstore_ftrace_record *)(src->old_log + src_off);
mrec = (struct pstore_ftrace_record *)(merged_buf);
while (dest_size > 0 && src_size > 0) {
if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
pstore_ftrace_read_timestamp(&srec[src_idx])) {
mrec[merged_idx++] = drec[dest_idx++];
dest_size -= record_size;
} else {
mrec[merged_idx++] = srec[src_idx++];
src_size -= record_size;
}
}
while (dest_size > 0) {
mrec[merged_idx++] = drec[dest_idx++];
dest_size -= record_size;
}
while (src_size > 0) {
mrec[merged_idx++] = srec[src_idx++];
src_size -= record_size;
}
kfree(dest->old_log);
dest->old_log = merged_buf;
dest->old_log_size = total;
return 0;
}
static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
int *count, struct timespec *time,
char **buf, bool *compressed,
ssize_t *ecc_notice_size,
struct pstore_info *psi)
{
ssize_t size;
ssize_t size = 0;
struct ramoops_context *cxt = psi->data;
struct persistent_ram_zone *prz = NULL;
int header_length = 0;
bool free_prz = false;
/* Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
* PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
@ -221,22 +274,56 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
if (!prz_ok(prz))
prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
1, id, type, PSTORE_TYPE_CONSOLE, 0);
if (!prz_ok(prz)) {
while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt && !prz) {
prz = ramoops_get_next_prz(cxt->fprzs,
&cxt->ftrace_read_cnt,
cxt->max_ftrace_cnt, id, type,
PSTORE_TYPE_FTRACE, 0);
if (!prz_ok(prz))
continue;
}
}
if (!prz_ok(prz))
prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
1, id, type, PSTORE_TYPE_PMSG, 0);
if (!prz_ok(prz))
return 0;
/* ftrace is last since it may want to dynamically allocate memory. */
if (!prz_ok(prz)) {
if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
prz = ramoops_get_next_prz(cxt->fprzs,
&cxt->ftrace_read_cnt, 1, id, type,
PSTORE_TYPE_FTRACE, 0);
} else {
/*
* Build a new dummy record which combines all the
* per-cpu records including metadata and ecc info.
*/
struct persistent_ram_zone *tmp_prz, *prz_next;
tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
GFP_KERNEL);
if (!tmp_prz)
return -ENOMEM;
free_prz = true;
while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
prz_next = ramoops_get_next_prz(cxt->fprzs,
&cxt->ftrace_read_cnt,
cxt->max_ftrace_cnt, id,
type, PSTORE_TYPE_FTRACE, 0);
if (!prz_ok(prz_next))
continue;
tmp_prz->ecc_info = prz_next->ecc_info;
tmp_prz->corrected_bytes +=
prz_next->corrected_bytes;
tmp_prz->bad_blocks += prz_next->bad_blocks;
size = ftrace_log_combine(tmp_prz, prz_next);
if (size)
goto out;
}
*id = 0;
prz = tmp_prz;
}
}
if (!prz_ok(prz)) {
size = 0;
goto out;
}
size = persistent_ram_old_size(prz) - header_length;
@ -244,12 +331,21 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
*ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
*buf = kmalloc(size + *ecc_notice_size + 1, GFP_KERNEL);
if (*buf == NULL)
return -ENOMEM;
if (*buf == NULL) {
size = -ENOMEM;
goto out;
}
memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size);
persistent_ram_ecc_string(prz, *buf + size, *ecc_notice_size + 1);
out:
if (free_prz) {
kfree(prz->old_log);
kfree(prz);
}
return size;
}