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Tue, 20 Oct 2026 05:10:32 -0700 (PDT) Received: from pathway.suse.cz ([176.114.240.130]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48e1d823cfcsm5747053f8f.39.2026.10.20.05.10.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Oct 2026 05:10:32 -0700 (PDT) Date: Tue, 20 Oct 2026 14:10:29 +0200 From: Petr Mladek To: Zack Rusin Cc: Andrew Morton , Baoquan He , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Dave Young , Borislav Petkov , Ajay Kaher , Alexey Makhalov , x86@kernel.org, Joel Granados , Thomas Gleixner , Ingo Molnar , Dave Hansen , "H. Peter Anvin" , virtualization@lists.linux.dev, bcm-kernel-feedback-list@broadcom.com, linux-kernel@vger.kernel.org, John Ogness , Steven Rostedt , Sergey Senozhatsky , Kees Cook , Jonathan Corbet , Bo Gan , Brennan Lamoreaux , kexec@lists.infradead.org, linux-doc@vger.kernel.org, "Guilherme G. Piccoli" , Maaz Mombasawala , Shuah Khan , Randy Dunlap , Stephen Brennan , Michael Kelley , Ian Forbes Subject: Re: [PATCH v2 2/6] crash: Notify pre-kdump callbacks before switching kernels Message-ID: References: <9ef573cdbbf5e659eea16fa23afeaf2488049198.1790014793.git.zack.rusin@broadcom.com> X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9ef573cdbbf5e659eea16fa23afeaf2488049198.1790014793.git.zack.rusin@broadcom.com> On Mon 2026-09-28 13:55:36, Zack Rusin wrote: > Fatal x86 oopses can call crash_kexec() without reaching panic(). Run the > pre-kdump chain from __crash_kexec() as well, after finding a loaded image > under the kexec lock and capturing the original registers. > > This covers direct crash entry without moving all panic notifiers ahead > of kdump. A missing image or failed trylock leaves callbacks uncalled; > the shared guard skips callbacks already invoked by panic(). > > Link: https://lore.kernel.org/r/aquttpMVKX8e6zGB@pathway.suse.cz > Signed-off-by: Zack Rusin > --- > New in v2: cover direct crash-kexec entry in a separate core patch. > > kernel/crash_core.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > index 2b36aa9fade0..5d9fe9e00f39 100644 > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -139,6 +140,7 @@ void __noclone __crash_kexec(struct pt_regs *regs) > struct pt_regs fixed_regs; > > crash_setup_regs(&fixed_regs, regs); > + panic_notify_pre_kdump(NULL); I understand why you did this. But it makes the code really hard to follow: + This code path will be called also by the 1st __crash_kexec() in vpanic() when "_crash_kexec_post_notifiers == false". It is the default. + The panic_notify_pre_kdump(buf) in vpanic(), added by 1st patch, is called when "_crash_kexec_post_notifiers == true" or when __crash_kexec() returns from some reason. None of this is obvious. I am going to think more about it. Best Regards, Petr > crash_save_vmcoreinfo(); > machine_crash_shutdown(&fixed_regs); > crash_cma_clear_pending_dma();