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Piccoli" , Thomas Zimmermann , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Shixiong Ou , Jinchao Wang , Zsolt Kajtar , Ingo Molnar , Nam Cao , Jonathan Cameron , Joel Fernandes , Joel Granados , Jason Gunthorpe , Sohil Mehta , Feng Tang , Sravan Kumar Gundu , Douglas Anderson , Thomas Gleixner , Anna Schumaker , "Darrick J. Wong" , Max Kellermann , Yunhui Cui , Tejun Heo , Luo Gengkun , Li Huafei , Thorsten Blum , Yicong Yang , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, kexec@lists.infradead.org, linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 3/9] crash_core: use panic_try_start() in crash_kexec() Date: Mon, 25 Aug 2025 10:29:31 +0800 Message-ID: <20250825022947.1596226-4-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250825022947.1596226-1-wangjinchao600@gmail.com> References: <20250825022947.1596226-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" crash_kexec() had its own code to exclude parallel execution by setting panic_cpu. This is already handled by panic_try_start(). Switch to panic_try_start() to remove the duplication and keep the logic consistent. Signed-off-by: Jinchao Wang --- kernel/crash_core.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) diff --git a/kernel/crash_core.c b/kernel/crash_core.c index a4ef79591eb2..bb38bbaf3a26 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -4,6 +4,7 @@ * Copyright (C) 2002-2004 Eric Biederman */ =20 +#include "linux/panic.h" #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt =20 #include @@ -143,17 +144,7 @@ STACK_FRAME_NON_STANDARD(__crash_kexec); =20 __bpf_kfunc void crash_kexec(struct pt_regs *regs) { - int old_cpu, this_cpu; - - /* - * Only one CPU is allowed to execute the crash_kexec() code as with - * panic(). Otherwise parallel calls of panic() and crash_kexec() - * may stop each other. To exclude them, we use panic_cpu here too. - */ - old_cpu =3D PANIC_CPU_INVALID; - this_cpu =3D raw_smp_processor_id(); - - if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) { + if (panic_try_start()) { /* This is the 1st CPU which comes here, so go ahead. */ __crash_kexec(regs); =20 @@ -161,7 +152,7 @@ __bpf_kfunc void crash_kexec(struct pt_regs *regs) * Reset panic_cpu to allow another panic()/crash_kexec() * call. */ - atomic_set(&panic_cpu, PANIC_CPU_INVALID); + panic_reset(); } } =20 --=20 2.43.0