On 8/10/23 22:45, Kees Cook wrote:
If an output buffer size exceeded U16_MAX, the min_t(u16, ...) cast in copy_data() was causing writes to truncate. This manifested as output bytes being skipped, seen as %NUL bytes in pstore dumps when the available record size was larger than 65536. Fix the cast to no longer truncate the calculation.
Cc: Petr Mladek pmladek@suse.com Cc: Sergey Senozhatsky senozhatsky@chromium.org Cc: Steven Rostedt rostedt@goodmis.org Cc: John Ogness john.ogness@linutronix.de Reported-by: Vijay Balakrishna vijayb@linux.microsoft.com Closes: https://lore.kernel.org/lkml/d8bb1ec7-a4c5-43a2-9de0-9643a70b899f@linux.micr... Fixes: b6cf8b3f3312 ("printk: add lockless ringbuffer") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org
Excellent.
I have verified on v5.10.
Tested-by: Vijay Balakrishna vijayb@linux.microsoft.com
Thanks, Vijay