Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] panic: Pre-kdump callbacks always receive NULL message in default config --
commit 8884313d127ae4b9734baebea7b4ba8dd25b38a5 Author: Zack Rusin <[email protected]> crash: Notify pre-kdump callbacks before switching kernels 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. Link: https://lore.kernel.org/r/[email protected] > the shared guard skips callbacks already invoked by panic(). [Severity: Medium] Is this statement accurate? During a standard panic-triggered kdump with crash_kexec_post_notifiers=0 (the default configuration), vpanic() calls __crash_kexec(NULL) before it formats the panic message and calls its own explicit panic_notify_pre_kdump(buf). Because __crash_kexec(NULL) runs first, won't the new panic_notify_pre_kdump(NULL) call consume the once-per-boot atomic guard, rather than being skipped by it? > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > index 2b36aa9fade06..5d9fe9e00f39f 100644 > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c [ ... ] > @@ -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); [Severity: Medium] Will this cause pre-kdump notifiers to receive a NULL message pointer instead of the expected panic message? If a system panic occurs and kexec is configured with the default setting of crash_kexec_post_notifiers=0, vpanic() triggers __crash_kexec(NULL) before reaching its own explicit panic_notify_pre_kdump(buf): kernel/panic.c:vpanic() { ... if (!_crash_kexec_post_notifiers) __crash_kexec(NULL); ... panic_notify_pre_kdump(buf); } When this happens, __crash_kexec() will invoke panic_notify_pre_kdump() with a NULL message pointer. This permanently consumes the once-per-boot guard, and any callback relying on the documented msg parameter will experience data loss or potential NULL dereferences, violating the API contract that promises the panic message during a panic. > crash_save_vmcoreinfo(); > machine_crash_shutdown(&fixed_regs); > crash_cma_clear_pending_dma(); -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=2
