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([2603:8080:7400:36da:dff5:4180:2562:4c1e]) by smtp.gmail.com with ESMTPSA id 006d021491bc7-60686e96d4esm285936eaf.8.2025.04.29.09.07.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 29 Apr 2025 09:07:20 -0700 (PDT) Message-ID: <575bdc12-be65-42a9-9581-e2a31e6ce810@gmail.com> Date: Tue, 29 Apr 2025 09:25:35 -0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/2] x86/panic: Add x86_panic_handler as default post-panic behavior To: Sean Christopherson , carlos.bilbao@kernel.org Cc: tglx@linutronix.de, jan.glauber@gmail.com, bilbao@vt.edu, pmladek@suse.com, akpm@linux-foundation.org, jani.nikula@intel.com, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, takakura@valinux.co.jp, john.ogness@linutronix.de References: <20250428215952.1332985-1-carlos.bilbao@kernel.org> <20250428215952.1332985-3-carlos.bilbao@kernel.org> Content-Language: en-US From: Carlos Bilbao In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hello, On 4/29/25 09:57, Sean Christopherson wrote: > On Mon, Apr 28, 2025, carlos.bilbao@kernel.org wrote: >> From: Carlos Bilbao >> >> Add function x86_panic_handler() as the default behavior for x86 for >> post-panic stage via panic_set_handling(). Instead of busy-wait loop, it >> will halt if there's no console to save CPU cycles. >> >> Signed-off-by: Carlos Bilbao (DigitalOcean) >> --- >> arch/x86/kernel/setup.c | 12 ++++++++++++ >> 1 file changed, 12 insertions(+) >> >> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c >> index 9d2a13b37833..3bfef55e9adb 100644 >> --- a/arch/x86/kernel/setup.c >> +++ b/arch/x86/kernel/setup.c >> @@ -16,6 +16,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -837,6 +838,15 @@ static void __init x86_report_nx(void) >> } >> } >> >> + > Spurious newline. > >> +static void x86_panic_handler(void) >> +{ >> + if (console_trylock()) { > A comment here would be very helpful. Even with the changelog saying "if there's > no console", as an unfamiliar reader of console code, I have zero idea why being > able to lock the console is an effective test for no console. Agree, will fix in v3. > >> + console_unlock(); >> + safe_halt(); >> + } >> +} Thanks, Carlos