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a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1708948912; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ssDX0tZ9H4aDFqTnUDa/YmbnpDQsXNRYjqJeEeUC+QE=; b=WQcV0biglPoBwnOItFsCWzHjvUl/N1wVCLQ5nLY9wqZ1XR2725+jHwPkHXinEzxQQ99pYX +sTn8tsf2SJRctmOnAANkkqHRakTEodjojHB0re/Uae21skTs9c6bD4W+9Z0RBiD663x9J tg1jLIgR8PlyjydI0vq4pMOYrJoXEgHzC+Obqrezs8KAHEbAaF1R8VTWCg1jjRZRdPaGBE McFYZTBWyXvaUBvTQznd9vEZz2zA95yUCPysb9dywex2vf9A5X5njTE3xQ5zkfA9B9vXDI Ks6xEwuvh86Ye5CM9MD249m3C4Y1qX9wElppfHozxFVm7zoYMlBpY2vZ2UVYlw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1708948912; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ssDX0tZ9H4aDFqTnUDa/YmbnpDQsXNRYjqJeEeUC+QE=; b=NficySbPs2/2+86UeilOXLw3LS+2zvXSEFsOG1gj3oGHWghV+YG4FqrrR+scflwoR/R644 FCHoSf3RhRG4EUAA== To: Mukesh Ojha , pmladek@suse.com, rostedt@goodmis.org, senozhatsky@chromium.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH] printk: Update @console_may_schedule in console_trylock_spinning() In-Reply-To: References: <20240222090538.23017-1-quic_mojha@quicinc.com> <87plwo5z4k.fsf@jogness.linutronix.de> Date: Mon, 26 Feb 2024 13:07:24 +0106 Message-ID: <875xybmo2z.fsf@jogness.linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1791962832347519315 X-GMAIL-MSGID: 1791962832347519315 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 Link: https://lore.kernel.org/lkml/20240222090538.23017-1-quic_mojha@quicinc.com Fixes: dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes") Signed-off-by: John Ogness Reviewed-by: Mukesh Ojha --- kernel/printk/printk.c | 6 ++++++ 1 file changed, 6 insertions(+) base-commit: e7081d5a9d976b84f61f497316d7c940a4a2e67a diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 1685a71f3f71..1612b50b2374 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2020,6 +2020,12 @@ 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; }