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authorLinus Torvalds <torvalds@linux-foundation.org>2021-04-27 18:09:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-27 18:09:44 -0700
commit7f3d08b255d1806502e45fe70ca2ba9646eb3aa1 (patch)
treeb05f285f31a37dac5910c40a643c7d38b19dfe3c /drivers
parent916a75965e5236f9e353416a703a0f4c8de2f56c (diff)
parentc8dbea6df351df211216b5f8877b020f21ecf75f (diff)
Merge tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek: - Stop synchronizing kernel log buffer readers by logbuf_lock. As a result, the access to the buffer is fully lockless now. Note that printk() itself still uses locks because it tries to flush the messages to the console immediately. Also the per-CPU temporary buffers are still there because they prevent infinite recursion and serialize backtraces from NMI. All this is going to change in the future. - kmsg_dump API rework and cleanup as a side effect of the logbuf_lock removal. - Make bstr_printf() aware that %pf and %pF formats could deference the given pointer. - Show also page flags by %pGp format. - Clarify the documentation for plain pointer printing. - Do not show no_hash_pointers warning multiple times. - Update Senozhatsky email address. - Some clean up. * tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (24 commits) lib/vsprintf.c: remove leftover 'f' and 'F' cases from bstr_printf() printk: clarify the documentation for plain pointer printing kernel/printk.c: Fixed mundane typos printk: rename vprintk_func to vprintk vsprintf: dump full information of page flags in pGp mm, slub: don't combine pr_err with INFO mm, slub: use pGp to print page flags MAINTAINERS: update Senozhatsky email address lib/vsprintf: do not show no_hash_pointers message multiple times printk: console: remove unnecessary safe buffer usage printk: kmsg_dump: remove _nolock() variants printk: remove logbuf_lock printk: introduce a kmsg_dump iterator printk: kmsg_dumper: remove @active field printk: add syslog_lock printk: use atomic64_t for devkmsg_user.seq printk: use seqcount_latch for clear_seq printk: introduce CONSOLE_LOG_MAX printk: consolidate kmsg_dump_get_buffer/syslog_print_all code printk: refactor kmsg_dump_get_buffer() ...
Diffstat (limited to 'drivers')
-rw-r--r--drivers/hv/vmbus_drv.c4
-rw-r--r--drivers/mtd/mtdoops.c17
2 files changed, 18 insertions, 3 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index b12d6827b222..92cb3f7d21d9 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1399,6 +1399,7 @@ static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id)
static void hv_kmsg_dump(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason)
{
+ struct kmsg_dump_iter iter;
size_t bytes_written;
/* We are only interested in panics. */
@@ -1409,7 +1410,8 @@ static void hv_kmsg_dump(struct kmsg_dumper *dumper,
* Write dump contents to the page. No need to synchronize; panic should
* be single-threaded.
*/
- kmsg_dump_get_buffer(dumper, false, hv_panic_page, HV_HYP_PAGE_SIZE,
+ kmsg_dump_rewind(&iter);
+ kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE,
&bytes_written);
if (!bytes_written)
return;
diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index 774970bfcf85..862c4a889234 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -52,6 +52,7 @@ static struct mtdoops_context {
int nextcount;
unsigned long *oops_page_used;
+ unsigned long oops_buf_busy;
void *oops_buf;
} oops_cxt;
@@ -180,6 +181,9 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic)
u32 *hdr;
int ret;
+ if (test_and_set_bit(0, &cxt->oops_buf_busy))
+ return;
+
/* Add mtdoops header to the buffer */
hdr = cxt->oops_buf;
hdr[0] = cxt->nextcount;
@@ -190,7 +194,7 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic)
record_size, &retlen, cxt->oops_buf);
if (ret == -EOPNOTSUPP) {
printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
- return;
+ goto out;
}
} else
ret = mtd_write(mtd, cxt->nextpage * record_size,
@@ -203,6 +207,8 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic)
memset(cxt->oops_buf, 0xff, record_size);
mtdoops_inc_counter(cxt);
+out:
+ clear_bit(0, &cxt->oops_buf_busy);
}
static void mtdoops_workfunc_write(struct work_struct *work)
@@ -271,13 +277,19 @@ static void mtdoops_do_dump(struct kmsg_dumper *dumper,
{
struct mtdoops_context *cxt = container_of(dumper,
struct mtdoops_context, dump);
+ struct kmsg_dump_iter iter;
/* Only dump oopses if dump_oops is set */
if (reason == KMSG_DUMP_OOPS && !dump_oops)
return;
- kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
+ kmsg_dump_rewind(&iter);
+
+ if (test_and_set_bit(0, &cxt->oops_buf_busy))
+ return;
+ kmsg_dump_get_buffer(&iter, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
record_size - MTDOOPS_HEADER_SIZE, NULL);
+ clear_bit(0, &cxt->oops_buf_busy);
if (reason != KMSG_DUMP_OOPS) {
/* Panics must be written immediately */
@@ -394,6 +406,7 @@ static int __init mtdoops_init(void)
return -ENOMEM;
}
memset(cxt->oops_buf, 0xff, record_size);
+ cxt->oops_buf_busy = 0;
INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);