From: Nathan Chancellor <nathan@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Rosen Penev <rosenp@gmail.com>,
linux-mm@kvack.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
"David Hildenbrand (Red Hat)" <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
"Vlastimil Babka (SUSE)" <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
open list <linux-kernel@vger.kernel.org>,
"open list:CLANG/LLVM BUILD SUPPORT:Keyword:b(?i:clang|llvm)b"
<llvm@lists.linux.dev>
Subject: Re: [PATCH] mm: move phys_mem_access_prot_allowed to header
Date: Wed, 6 May 2026 13:48:28 +0800 [thread overview]
Message-ID: <20260506054828.GA8550@ax162> (raw)
In-Reply-To: <add152a5-09bb-4c6b-a17f-da3d817b93e9@app.fastmail.com>
On Tue, May 05, 2026 at 11:22:13AM +0200, Arnd Bergmann wrote:
> On Tue, May 5, 2026, at 10:54, Rosen Penev wrote:
> > On Tue, May 5, 2026 at 1:29 AM Arnd Bergmann <arnd@arndb.de> wrote:
> >>
> >> Does this happen with both ld.bfd and ld.lld? Which version of clang
> >> and lld are you using?
> > clang version 22.1.3
> > Target: x86_64-pc-linux-gnu
> > Thread model: posix
> > InstalledDir: /usr/bin
> >
> > lld the same.
>
> Ok. I've tried to reproduce this with Nathan's llvm-22.1.3 build
> from https://mirrors.edge.kernel.org/pub/tools/llvm/, but don't
> see this problem on mips defconfig. Are you using a particular
> configuration, or do you see this on every build?
This is just the same old integrated assembler vs. recordmcount bug:
https://github.com/ClangBuiltLinux/linux/issues/981
https://github.com/ClangBuiltLinux/linux/issues/1830
It requires CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y with ftrace, which
MIPS allmodconfig enables. PowerPC worked around this in commit
f8b2336f15f3 ("powerpc: Avoid dead code/data elimination when using
recordmcount"). Maybe something along the same lines should be done for
MIPS.
Cheers,
Nathan
next prev parent reply other threads:[~2026-05-06 5:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-05 1:01 [PATCH] mm: move phys_mem_access_prot_allowed to header Rosen Penev
2026-05-05 5:54 ` Arnd Bergmann
2026-05-05 7:47 ` Rosen Penev
2026-05-05 8:29 ` Arnd Bergmann
2026-05-05 8:54 ` Rosen Penev
2026-05-05 9:22 ` Arnd Bergmann
2026-05-05 22:36 ` Rosen Penev
2026-05-06 5:48 ` Nathan Chancellor [this message]
2026-05-06 6:02 ` Rosen Penev
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