4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: John Ogness <john.ogness@xxxxxxxxxxxxx> [ Upstream commit 8076972468584d4a21dab9aa50e388b3ea9ad8c7 ] console_trylock_spinning() may takeover the console lock from a schedulable context. Update @console_may_schedule to make sure it reflects a trylock acquire. Reported-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx> Closes: https://lore.kernel.org/lkml/20240222090538.23017-1-quic_mojha@xxxxxxxxxxx Fixes: dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes") Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx> Reviewed-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx> Reviewed-by: Petr Mladek <pmladek@xxxxxxxx> Link: https://lore.kernel.org/r/875xybmo2z.fsf@xxxxxxxxxxxxxxxxxxxxx Signed-off-by: Petr Mladek <pmladek@xxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- kernel/printk/printk.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 2ba16c426ba5d..66c78dfd17925 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1732,6 +1732,12 @@ static int console_trylock_spinning(void) */ mutex_acquire(&console_lock_dep_map, 0, 1, _THIS_IP_); + /* + * Update @console_may_schedule for trylock because the previous + * owner may have been schedulable. + */ + console_may_schedule = 0; + return 1; } -- 2.43.0
