diff options
| author | Pavel Tatashin | 2020-05-05 11:45:06 -0400 |
|---|---|---|
| committer | Kees Cook | 2020-05-30 10:34:03 -0700 |
| commit | b1f6f161b236d0e5a9222fb8b482e65aaff13689 (patch) | |
| tree | e5cf158f2ddb84fa36502e54b1b87092a53291b9 | |
| parent | 6d3cf962dd1a95df868c547b090bfc4c7977f4be (diff) | |
printk: honor the max_reason field in kmsg_dumper
kmsg_dump() allows to dump kmesg buffer for various system events: oops,
panic, reboot, etc. It provides an interface to register a callback
call for clients, and in that callback interface there is a field
"max_reason", but it was getting ignored when set to any "reason"
higher than KMSG_DUMP_OOPS unless "always_kmsg_dump" was passed as
kernel parameter.
Allow clients to actually control their "max_reason", and keep the
current behavior when "max_reason" is not set.
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/lkml/20200515184434.8470-3-keescook@chromium.org/
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
| -rw-r--r-- | include/linux/kmsg_dump.h | 1 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 15 |
2 files changed, 12 insertions, 4 deletions
diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 3f82b5cb2d82..9826014771ab 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -26,6 +26,7 @@ enum kmsg_dump_reason { KMSG_DUMP_OOPS, KMSG_DUMP_EMERG, KMSG_DUMP_SHUTDOWN, + KMSG_DUMP_MAX }; /** diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 9a9b6156270b..a121c2255737 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3157,12 +3157,19 @@ void kmsg_dump(enum kmsg_dump_reason reason) struct kmsg_dumper *dumper; unsigned long flags; - if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) - return; - rcu_read_lock(); list_for_each_entry_rcu(dumper, &dump_list, list) { - if (dumper->max_reason && reason > dumper->max_reason) + enum kmsg_dump_reason max_reason = dumper->max_reason; + + /* + * If client has not provided a specific max_reason, default + * to KMSG_DUMP_OOPS, unless always_kmsg_dump was set. + */ + if (max_reason == KMSG_DUMP_UNDEF) { + max_reason = always_kmsg_dump ? KMSG_DUMP_MAX : + KMSG_DUMP_OOPS; + } + if (reason > max_reason) continue; /* initialize iterator with data about the stored records */ |