From 90574a9c02f1ed46d9d8fec222fbcf375eb90e9b Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Fri, 6 Nov 2020 04:40:05 +0100 Subject: printk: remove unneeded dead-store assignment make clang-analyzer on x86_64 defconfig caught my attention with: kernel/printk/printk_ringbuffer.c:885:3: warning: Value stored to 'desc' is never read [clang-analyzer-deadcode.DeadStores] desc = to_desc(desc_ring, head_id); ^ Commit b6cf8b3f3312 ("printk: add lockless ringbuffer") introduced desc_reserve() with this unneeded dead-store assignment. As discussed with John Ogness privately, this is probably just some minor left-over from previous iterations of the ringbuffer implementation. So, simply remove this unneeded dead assignment to make clang-analyzer happy. As compilers will detect this unneeded assignment and optimize this anyway, the resulting object code is identical before and after this change. No functional change. No change to object code. Signed-off-by: Lukas Bulwahn Reviewed-by: Sergey Senozhatsky Reviewed-by: John Ogness Reviewed-by: Nathan Chancellor Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20201106034005.18822-1-lukas.bulwahn@gmail.com --- kernel/printk/printk_ringbuffer.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel/printk') diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c index 24a960a89aa8..dd43c4cf16fb 100644 --- a/kernel/printk/printk_ringbuffer.c +++ b/kernel/printk/printk_ringbuffer.c @@ -882,8 +882,6 @@ static bool desc_reserve(struct printk_ringbuffer *rb, unsigned long *id_out) head_id = atomic_long_read(&desc_ring->head_id); /* LMM(desc_reserve:A) */ do { - desc = to_desc(desc_ring, head_id); - id = DESC_ID(head_id + 1); id_prev_wrap = DESC_ID_PREV_WRAP(desc_ring, id); -- cgit v1.2.3 From 4ad9921af4f18490980369f7d60f90ade0195812 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Thu, 26 Nov 2020 12:54:36 +0106 Subject: printk: finalize records with trailing newlines Any record with a trailing newline (LOG_NEWLINE flag) cannot be continued because the newline has been stripped and will not be visible if the message is appended. This was already handled correctly when committing in log_output() but was not handled correctly when committing in log_store(). Fixes: f5f022e53b87 ("printk: reimplement log_cont using record extension") Link: https://lore.kernel.org/r/20201126114836.14750-1-john.ogness@linutronix.de Reported-by: Kefeng Wang Signed-off-by: John Ogness Tested-by: Kefeng Wang Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/printk') diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index fe64a49344bf..bc1e3b5a97bd 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -528,8 +528,8 @@ static int log_store(u32 caller_id, int facility, int level, if (dev_info) memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info)); - /* insert message */ - if ((flags & LOG_CONT) || !(flags & LOG_NEWLINE)) + /* A message without a trailing newline can be continued. */ + if (!(flags & LOG_NEWLINE)) prb_commit(&e); else prb_final_commit(&e); -- cgit v1.2.3