Message-ID: <sashiko-outbox-204467@kernel.org>
From: sashiko-bot@kernel.org
Subject: Re: [PATCH v3 1/4] panic: Add a platform panic notifier list
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To: "Zack Rusin" <zack.rusin@broadcom.com>, "Andrew Morton" <akpm@linux-foundation.org>, "Petr
 Mladek" <pmladek@suse.com>, "Baoquan He" <baoquan.he@linux.dev>, "Mike
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 Yadav" <pratyush@kernel.org>, "Dave Young" <ruirui.yang@linux.dev>
Cc: "Borislav Petkov" <bp@alien8.de>, "Ajay Kaher" <ajay.kaher@broadcom.com>, "Alexey
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 Gleixner" <tglx@kernel.org>, "Ingo Molnar" <mingo@redhat.com>, "Dave Hansen" <dave.hansen@linux.intel.com>, "H.
 Peter Anvin" <hpa@zytor.com>, virtualization@lists.linux.dev, bcm-kernel-feedback-list@broadcom.com, "John
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 Lamoreaux" <brennan.lamoreaux@broadcom.com>, kexec@lists.infradead.org, "Guilherme
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In-Reply-To: <42090fa4453561ebc35f35cc563ec79933eebe75.1794201807.git.zack.rusin@broadcom.com>
References: <cover.1794201807.git.zack.rusin@broadcom.com>
 <42090fa4453561ebc35f35cc563ec79933eebe75.1794201807.git.zack.rusin@broadcom.com>
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Date: Mon, 09 Nov 2026 05:58:16 +0000
Precedence: list

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Medium] crash: kexec_trylock() held across panic_notify_platform()
  breaks kdump
--

commit 27b42ef2d74e73a1aad7b08a71b2e46383b32891
Author: Zack Rusin <zack.rusin@broadcom.com>

panic: Add a platform panic notifier list

This commit adds a platform panic notifier list (panic_notifiers_platform_l=
ist)
that runs early in vpanic() and in __crash_kexec(), along with a kernel
parameter to disable it.

Link: https://lore.kernel.org/r/ateYxCu63pRY9EGq@pathway.suse.cz

> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index d0bd2d0cf8990..10b4384294c2b 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
[ ... ]
> @@ -139,6 +140,8 @@ void __noclone __crash_kexec(struct pt_regs *regs)
>  			struct pt_regs fixed_regs;
> =20
>  			crash_setup_regs(&fixed_regs, regs);
> +			/* For crash paths that bypass panic() */
> +			panic_notify_platform();
>  			crash_save_vmcoreinfo();
>  			machine_crash_shutdown(&fixed_regs);
>  			crash_cma_clear_pending_dma();

[Severity: Medium]
Can calling panic_notify_platform() while kexec_trylock() is held prevent
kdump from running if a platform notifier callback panics?

panic_notify_platform() sets done =3D true before invoking the notifier
chain so that a callback that panics will not re-run the list when it
enters vpanic().  However, when __crash_kexec() is entered directly on a
crash path that bypasses panic() (such as oops_end() -> crash_kexec()),
__kexec_lock is already held:

  crash_kexec()
    __crash_kexec(regs)
      kexec_trylock()
      panic_notify_platform()
        <callback panics>
          vpanic()
            __crash_kexec(NULL)
              kexec_trylock()  <-- fails, skips kdump

Because vpanic() never returns to the outer __crash_kexec() frame,
machine_kexec() is never reached and the crash dump is lost.

--=20
Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/cover.1794201807.gi=
t.zack.rusin@broadcom.com?part=3D1