linux-kernel - Re: [PATCH] MIPS: Ignore relocs against __ex

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Message-ID: <Z79ZD3EL1Q8UjaFH@alpha.franken.de>
Date: Wed, 26 Feb 2025 19:10:23 +0100
From: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Xi Ruoyao <xry111@...111.site>, Jiaxun Yang <jiaxun.yang@...goat.com>,
	Matt Redfearn <matt.redfearn@...ize.com>,
	linux-mips@...r.kernel.org, linux-kbuild@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] MIPS: Ignore relocs against __ex_table for relocatable
 kernel

On Wed, Feb 26, 2025 at 10:43:40AM -0500, Steven Rostedt wrote:
> On Wed, 26 Feb 2025 21:28:41 +0800
> Xi Ruoyao <xry111@...111.site> wrote:
> 
> > Since commit 6f2c2f93a190 ("scripts/sorttable: Remove unneeded
> > Elf_Rel"), sorttable no longer clears relocs against __ex_table,
> > claiming "it was never used."  But in fact MIPS relocatable kernel had
> > been implicitly depending on this behavior, so after this commit the
> > MIPS relocatable kernel has started to spit oops like:
> 
>  Oops!
> 
> > 
> > 	CPU 1 Unable to handle kernel paging request at virtual address 000000fffbbdbff8, epc == ffffffff818f9a6c, ra == ffffffff813ad7d0
> > 	... ...
> > 	Call Trace:
> > 	[<ffffffff818f9a6c>] __raw_copy_from_user+0x48/0x2fc
> > 	[<ffffffff813ad7d0>] cp_statx+0x1a0/0x1e0
> > 	[<ffffffff813ae528>] do_statx_fd+0xa8/0x118
> > 	[<ffffffff813ae670>] sys_statx+0xd8/0xf8
> > 	[<ffffffff81156cc8>] syscall_common+0x34/0x58
> > 
> > So ignore those relocs on our own to fix the issue.
> > 
> > Fixes: 6f2c2f93a190 ("scripts/sorttable: Remove unneeded Elf_Rel")
> > Signed-off-by: Xi Ruoyao <xry111@...111.site>
> 
> Thanks! Yeah, this is better than having an implicit dependency to the
> sorttable code.
> 
> I take it that this will go through the mips tree?

yes, I'll take it.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]