Re: [GIT PULL] runtime verification: Updates for 6.17

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Sat, Aug 16, 2025 at 02:04:34PM +0200, Richard Weinberger wrote:
> [Adding ARM folks]
> 
> On Tue, Jul 29, 2025 at 11:43 PM Steven Rostedt <rostedt@goodmis.org> wrote:
> > Linus,
> >
> > Runtime verification changes for 6.17
> 
> [...]
> 
> > - Add a vpanic() to allow for va_list to be passed to panic.
> 
> This change is causing a regression on ARM32.
> panic() no longer shows a proper stack trace.
> 
> With this change:
> [    2.943690] Kernel panic - not syncing: VFS: Unable to mount root
> fs on unknown-block(0,0)
> [    2.950101] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted
> 6.17.0-rc1 #176 NONE
> [    2.950509] Hardware name: Generic DT based system
> [    2.950865] Call trace:
> [    2.951722]  unwind_backtrace from show_stack+0x18/0x1c
> [    2.953111]  show_stack from dump_stack_lvl+0x54/0x68
> [    2.953312]  dump_stack_lvl from vpanic+0xf8/0x388
> [    2.953526]  vpanic from __do_trace_suspend_resume+0x0/0x50

Please lookup the value of __do_trace_suspend_resume in System.map.

> 
> With commit  3f045de7f5 "panic: Add vpanic()" reverted:
> [    2.680077] Kernel panic - not syncing: VFS: Unable to mount root
> fs on unknown-block(0,0)
> [    2.690241] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted
> 6.17.0-rc1-dirty #177 NONE
> [    2.690832] Hardware name: Generic DT based system
> [    2.691339] Call trace:
> [    2.692530]  unwind_backtrace from show_stack+0x18/0x1c
> [    2.694283]  show_stack from dump_stack_lvl+0x54/0x68
> [    2.694536]  dump_stack_lvl from panic+0x110/0x31c
> [    2.694944]  panic from mount_root_generic+0x1fc/0x2ac

Also please lookup mount_root_generic.

> Maybe it changes the stack layout enough such that dump_stack() on
> ARM32 is no longer
> able to walk it? I'm using gcc 15.1.1, if this matters.

Also please check whether you're using frame pointers or the unwinder
(CONFIG_UNWINDER_FRAME_POINTER or CONFIG_ARM_UNWIND).

Thanks.

-- 
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