fixes for 4.4

Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/queue-4.4/printk-do-not-lose-last-line-in-kmsg-buffer-dump.patch b/queue-4.4/printk-do-not-lose-last-line-in-kmsg-buffer-dump.patch
new file mode 100644 (file)
index 0000000..24ad7f3
--- /dev/null
+++ b/queue-4.4/printk-do-not-lose-last-line-in-kmsg-buffer-dump.patch
@@ -0,0 +1,74 @@
+From 223d596ac27e6e6c9e4585891f54d9ac067dbec2 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Thu, 11 Jul 2019 16:29:37 +0200
+Subject: printk: Do not lose last line in kmsg buffer dump
+
+From: Vincent Whitchurch <vincent.whitchurch@axis.com>
+
+[ Upstream commit b46eff55ad5bd98e746c0a7022fe7ee071de5fee ]
+
+kmsg_dump_get_buffer() is supposed to select all the youngest log
+messages which fit into the provided buffer.  It determines the correct
+start index by using msg_print_text() with a NULL buffer to calculate
+the size of each entry.  However, when performing the actual writes,
+msg_print_text() only writes the entry to the buffer if the written len
+is lesser than the size of the buffer.  So if the lengths of the
+selected youngest log messages happen to precisely fill up the provided
+buffer, the last log message is not included.
+
+We don't want to modify msg_print_text() to fill up the buffer and start
+returning a length which is equal to the size of the buffer, since
+callers of its other users, such as kmsg_dump_get_line(), depend upon
+the current behaviour.
+
+Instead, fix kmsg_dump_get_buffer() to compensate for this.
+
+For example, with the following two final prints:
+
+[    6.427502] AAAAAAAAAAAAA
+[    6.427769] BBBBBBBB12345
+
+A dump of a 64-byte buffer filled by kmsg_dump_get_buffer(), before this
+patch:
+
+ 00000000: 3c 30 3e 5b 20 20 20 20 36 2e 35 32 32 31 39 37  <0>[    6.522197
+ 00000010: 5d 20 41 41 41 41 41 41 41 41 41 41 41 41 41 0a  ] AAAAAAAAAAAAA.
+ 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
+ 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
+
+After this patch:
+
+ 00000000: 3c 30 3e 5b 20 20 20 20 36 2e 34 35 36 36 37 38  <0>[    6.456678
+ 00000010: 5d 20 42 42 42 42 42 42 42 42 31 32 33 34 35 0a  ] BBBBBBBB12345.
+ 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
+ 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
+
+Link: http://lkml.kernel.org/r/20190711142937.4083-1-vincent.whitchurch@axis.com
+Fixes: e2ae715d66bf4bec ("kmsg - kmsg_dump() use iterator to receive log buffer content")
+To: rostedt@goodmis.org
+Cc: linux-kernel@vger.kernel.org
+Cc: <stable@vger.kernel.org> # v3.5+
+Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
+Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Signed-off-by: Petr Mladek <pmladek@suse.com>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ kernel/printk/printk.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index dd689ab228065..5a1b2a914b4e5 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -3048,7 +3048,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+       seq = dumper->cur_seq;
+       idx = dumper->cur_idx;
+       prev = 0;
+-      while (l > size && seq < dumper->next_seq) {
++      while (l >= size && seq < dumper->next_seq) {
+               struct printk_log *msg = log_from_idx(idx);
+ 
+               l -= msg_print_text(msg, prev, true, NULL, 0);
+-- 
+2.20.1
+

diff --git a/queue-4.4/series b/queue-4.4/series
index e2e979e54bc674cba99a9afafa929af1ac58af43..348a675176b3136241b47cbc70bbd207876b229f 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -75,3 +75,4 @@ btrfs-extent-tree-make-sure-we-only-allocate-extents.patch
 media-omap3isp-set-device-on-omap3isp-subdevs.patch
 alsa-firewire-tascam-handle-error-code-when-getting-current-source-of-clock.patch
 alsa-firewire-tascam-check-intermediate-state-of-clock-status-and-retry.patch
+printk-do-not-lose-last-line-in-kmsg-buffer-dump.patch