From: Yonghong Song <yonghong.song@linux.dev>
To: Alan Maguire <alan.maguire@oracle.com>,
kees@kernel.org, nathan@kernel.org, peterz@infradead.org,
elver@google.com
Cc: ojeda@kernel.org, akpm@linux-foundation.org, ubizjak@gmail.com,
Jason@zx2c4.com, Marc.Herbert@linux.intel.com, hca@linux.ibm.com,
hpa@zytor.com, namjain@linux.microsoft.com, paulmck@kernel.org,
linux-kernel@vger.kernel.org, andrii.nakryiko@gmail.com,
ast@kernel.org, jolsa@kernel.org, daniel@iogearbox.net,
martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me,
haoluo@google.com, bvanassche@acm.org, nilay@linux.ibm.com,
bpf@vger.kernel.org
Subject: Re: [PATCH] kcsan, compiler_types: avoid duplicate type issues in BPF Type Format
Date: Fri, 16 Jan 2026 09:26:49 -0800 [thread overview]
Message-ID: <8131f46b-7115-44db-b182-9471afa67e61@linux.dev> (raw)
In-Reply-To: <20260116091730.324322-1-alan.maguire@oracle.com>
On 1/16/26 1:17 AM, Alan Maguire wrote:
> Enabling KCSAN is causing a large number of duplicate types
> in BTF for core kernel structs like task_struct [1].
> This is due to the definition in include/linux/compiler_types.h
>
> `#ifdef __SANITIZE_THREAD__
> ...
> `#define __data_racy volatile
> ..
> `#else
> ...
> `#define __data_racy
> ...
> `#endif
>
> Because some objects in the kernel are compiled without
> KCSAN flags (KCSAN_SANITIZE) we sometimes get the empty
> __data_racy annotation for objects; as a result we get multiple
> conflicting representations of the associated structs in DWARF,
> and these lead to multiple instances of core kernel types in
> BTF since they cannot be deduplicated due to the additional
> modifier in some instances.
>
> Moving the __data_racy definition under CONFIG_KCSAN
> avoids this problem, since the volatile modifier will
> be present for both KCSAN and KCSAN_SANITIZE objects
> in a CONFIG_KCSAN=y kernel.
>
> Fixes: 31f605a308e6 ("kcsan, compiler_types: Introduce __data_racy type qualifier")
> Reported-by: Nilay Shroff <nilay@linux.ibm.com>
> Suggested-by: Marco Elver <elver@google.com>
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Tested on gcc15 and llvm22 and all works okay. Also
the patch itself makes sense, so
Acked-by: Yonghong Song <yonghong.song@linux.dev>
prev parent reply other threads:[~2026-01-16 17:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-16 9:17 [PATCH] kcsan, compiler_types: avoid duplicate type issues in BPF Type Format Alan Maguire
2026-01-16 10:13 ` Marco Elver
2026-01-27 23:08 ` Marco Elver
2026-01-27 23:31 ` Andrew Morton
2026-01-28 0:02 ` Alexei Starovoitov
2026-01-28 1:04 ` Andrew Morton
2026-01-28 1:44 ` Marco Elver
2026-01-16 13:15 ` Nilay Shroff
2026-01-16 17:26 ` Yonghong Song [this message]
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