Messages in this thread Patch in this message | | | From | John Ogness <> | Subject | [PATCH] printk: kmsg_dump: revert msg_print_text() workaround | Date | Thu, 14 Jan 2021 10:11:11 +0106 |
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The old msg_print_text() function only filled up to size-1 bytes of the buffer. A workaround for this quirky behavior was implemented with commit c9dccacfccc7 ("printk: Do not lose last line in kmsg buffer dump").
However, with commit 896fbe20b4e2 ("printk: use the lockless ringbuffer"), msg_print_text() was replaced by record_print_text(), which will fill the full buffer. Therefore, the workaround is now incorrectly assuming less data can fit into the buffer. Revert the workaround.
Fixes: 896fbe20b4e2 ("printk: use the lockless ringbuffer") Signed-off-by: John Ogness <john.ogness@linutronix.de> --- This patch is on top of https://lkml.kernel.org/r/20210113164413.1599-1-john.ogness@linutronix.de and possibly could be squashed into that patch. However I recommend keeping them separate since they affect kmsg_dump_get_buffer() in different ways.
kernel/printk/printk.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 848b56efc9d7..489b9330f7f7 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3433,8 +3433,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, /* move first record forward until length fits into the buffer */ seq = dumper->cur_seq; - while (l >= size && prb_read_valid_info(prb, seq, - &info, &line_count)) { + while (l > size && prb_read_valid_info(prb, seq, &info, &line_count)) { if (r.info->seq >= dumper->next_seq) break; l -= get_record_print_text_size(&info, line_count, syslog, time); -- 2.20.1
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