This is a note to let you know that I've just added the patch titled kdb: Fix pager search for multi-line strings to the 5.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kdb-fix-pager-search-for-multi-line-strings.patch and it can be found in the queue-5.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit f1c68edcbc08ec86e74c0f08252fc46ab105ba8f Author: Daniel Thompson <daniel.thompson@xxxxxxxxxx> Date: Wed Sep 9 15:17:08 2020 +0100 kdb: Fix pager search for multi-line strings [ Upstream commit d081a6e353168f15e63eb9e9334757f20343319f ] Currently using forward search doesn't handle multi-line strings correctly. The search routine replaces line breaks with \0 during the search and, for regular searches ("help | grep Common\n"), there is code after the line has been discarded or printed to replace the break character. However during a pager search ("help\n" followed by "/Common\n") when the string is matched we will immediately return to normal output and the code that should restore the \n becomes unreachable. Fix this by restoring the replaced character when we disable the search mode and update the comment accordingly. Fixes: fb6daa7520f9d ("kdb: Provide forward search at more prompt") Link: https://lore.kernel.org/r/20200909141708.338273-1-daniel.thompson@xxxxxxxxxx Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx> Signed-off-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index 683a799618ade..bc827bd547c81 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -706,12 +706,16 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap) size_avail = sizeof(kdb_buffer) - len; goto kdb_print_out; } - if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) + if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) { /* * This was a interactive search (using '/' at more - * prompt) and it has completed. Clear the flag. + * prompt) and it has completed. Replace the \0 with + * its original value to ensure multi-line strings + * are handled properly, and return to normal mode. */ + *cphold = replaced_byte; kdb_grepping_flag = 0; + } /* * at this point the string is a full line and * should be printed, up to the null.