diff mbox series

[5.4,241/408] kdb: Fix pager search for multi-line strings

Message ID 20201027135506.238150584@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Oct. 27, 2020, 1:52 p.m. UTC 
From: Daniel Thompson <daniel.thompson@linaro.org>

[ 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@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/debug/kdb/kdb_io.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 3a5184eb6977d..46821793637a1 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -679,12 +679,16 @@  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.