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From: Nick Desaulniers <ndesaulniers@google.com>
To: akpm@linux-foundation.org
Cc: sedat.dilek@gmail.com, jpoimboe@redhat.com, yhs@fb.com,
	miguel.ojeda.sandonis@gmail.com,
	clang-built-linux@googlegroups.com,
	Nick Desaulniers <ndesaulniers@google.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH 00/16] treewide: prefer __section from compiler_attributes.h
Date: Mon, 12 Aug 2019 14:50:50 -0700	[thread overview]
Message-ID: <20190812215052.71840-17-ndesaulniers@google.com> (raw)
In-Reply-To: <20190812215052.71840-1-ndesaulniers@google.com>

GCC unescapes escaped string section names while Clang does not. Because
__section uses the `#` stringification operator for the section name, it
doesn't need to be escaped.

This fixes an Oops observed in distro's that use systemd and not
net.core.bpf_jit_enable=1, when their kernels are compiled with Clang.

Instead, we should:
1. Prefer __section(.section_name_no_quotes).
2. Only use __attribute__((__section(".section"))) when creating the
section name via C preprocessor (see the definition of __define_initcall
in arch/um/include/shared/init.h).

This antipattern was found with:
$ grep -e __section\(\" -e __section__\(\" -r

See the discussions in:
https://bugs.llvm.org/show_bug.cgi?id=42950
https://marc.info/?l=linux-netdev&m=156412960619946&w=2

Nick Desaulniers (16):
  s390/boot: fix section name escaping
  arc: prefer __section from compiler_attributes.h
  parisc: prefer __section from compiler_attributes.h
  um: prefer __section from compiler_attributes.h
  sh: prefer __section from compiler_attributes.h
  ia64: prefer __section from compiler_attributes.h
  arm: prefer __section from compiler_attributes.h
  mips: prefer __section from compiler_attributes.h
  sparc: prefer __section from compiler_attributes.h
  powerpc: prefer __section and __printf from compiler_attributes.h
  x86: prefer __section from compiler_attributes.h
  arm64: prefer __section from compiler_attributes.h
  include/asm-generic: prefer __section from compiler_attributes.h
  include/linux: prefer __section from compiler_attributes.h
  include/linux/compiler.h: remove unused KENTRY macro
  compiler_attributes.h: add note about __section

 arch/arc/include/asm/linkage.h        |  8 +++----
 arch/arc/include/asm/mach_desc.h      |  3 +--
 arch/arm/include/asm/cache.h          |  2 +-
 arch/arm/include/asm/mach/arch.h      |  4 ++--
 arch/arm/include/asm/setup.h          |  2 +-
 arch/arm64/include/asm/cache.h        |  2 +-
 arch/arm64/kernel/smp_spin_table.c    |  2 +-
 arch/ia64/include/asm/cache.h         |  2 +-
 arch/mips/include/asm/cache.h         |  2 +-
 arch/parisc/include/asm/cache.h       |  2 +-
 arch/parisc/include/asm/ldcw.h        |  2 +-
 arch/powerpc/boot/main.c              |  3 +--
 arch/powerpc/boot/ps3.c               |  6 ++----
 arch/powerpc/include/asm/cache.h      |  2 +-
 arch/powerpc/kernel/btext.c           |  2 +-
 arch/s390/boot/startup.c              |  2 +-
 arch/sh/include/asm/cache.h           |  2 +-
 arch/sparc/include/asm/cache.h        |  2 +-
 arch/sparc/kernel/btext.c             |  2 +-
 arch/um/kernel/um_arch.c              |  6 +++---
 arch/x86/include/asm/cache.h          |  2 +-
 arch/x86/include/asm/intel-mid.h      |  2 +-
 arch/x86/include/asm/iommu_table.h    |  5 ++---
 arch/x86/include/asm/irqflags.h       |  2 +-
 arch/x86/include/asm/mem_encrypt.h    |  2 +-
 arch/x86/kernel/cpu/cpu.h             |  3 +--
 include/asm-generic/error-injection.h |  2 +-
 include/asm-generic/kprobes.h         |  5 ++---
 include/linux/cache.h                 |  6 +++---
 include/linux/compiler.h              | 31 ++++-----------------------
 include/linux/compiler_attributes.h   | 10 +++++++++
 include/linux/cpu.h                   |  2 +-
 include/linux/export.h                |  2 +-
 include/linux/init_task.h             |  4 ++--
 include/linux/interrupt.h             |  5 ++---
 include/linux/sched/debug.h           |  2 +-
 include/linux/srcutree.h              |  2 +-
 37 files changed, 62 insertions(+), 83 deletions(-)

-- 
2.23.0.rc1.153.gdeed80330f-goog


  parent reply	other threads:[~2019-08-12 21:53 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-12 21:50 [PATCH 01/16] s390/boot: fix section name escaping Nick Desaulniers
2019-08-12 21:50 ` [PATCH 02/16] arc: prefer __section from compiler_attributes.h Nick Desaulniers
2019-08-12 21:50 ` [PATCH 03/16] parisc: " Nick Desaulniers
2019-08-12 21:50 ` [PATCH 04/16] um: " Nick Desaulniers
2019-08-12 21:50 ` [PATCH 05/16] sh: " Nick Desaulniers
2019-08-13  8:51   ` Yoshinori Sato
2019-08-12 21:50 ` [PATCH 06/16] ia64: " Nick Desaulniers
2019-08-12 21:50 ` [PATCH 07/16] arm: " Nick Desaulniers
2019-08-12 21:50 ` [PATCH 08/16] mips: " Nick Desaulniers
2019-08-15  9:38   ` Paul Burton
2019-08-27  0:19     ` Nick Desaulniers
2019-08-12 21:50 ` [PATCH 09/16] sparc: " Nick Desaulniers
2019-08-12 22:13   ` David Miller
2019-08-12 21:50 ` [PATCH 10/16] powerpc: prefer __section and __printf " Nick Desaulniers
2020-04-01 12:53   ` Michael Ellerman
2020-04-01 13:18     ` Miguel Ojeda
2019-08-12 21:50 ` [PATCH 11/16] x86: prefer __section " Nick Desaulniers
2019-08-19 10:31   ` Thomas Gleixner
2019-08-19 17:59   ` Sedat Dilek
2019-08-12 21:50 ` [PATCH 12/16] arm64: " Nick Desaulniers
2019-08-13  8:27   ` Will Deacon
2019-08-13 12:36     ` Miguel Ojeda
2019-08-13 17:08       ` Will Deacon
2019-08-14 22:20         ` Nick Desaulniers
2019-08-15  9:08           ` Miguel Ojeda
2019-08-15  9:12             ` Miguel Ojeda
2019-08-23 19:35               ` Miguel Ojeda
2019-08-24 11:25                 ` Will Deacon
2019-08-24 12:48                   ` Miguel Ojeda
2019-08-26 17:03                     ` Nick Desaulniers
2019-08-12 21:50 ` [PATCH 13/16] include/asm-generic: " Nick Desaulniers
2019-08-13  7:57   ` Arnd Bergmann
2019-08-19 17:52   ` Naveen N. Rao
2019-08-19 17:56     ` Sedat Dilek
2019-08-12 21:50 ` [PATCH 14/16] include/linux: " Nick Desaulniers
2019-08-13  8:31   ` Ard Biesheuvel
2019-08-13  8:32   ` Will Deacon
2019-08-24 12:51     ` Miguel Ojeda
2019-08-27  8:21       ` Will Deacon
2019-08-19 18:05   ` Sedat Dilek
2019-08-12 21:50 ` [PATCH 15/16] include/linux/compiler.h: remove unused KENTRY macro Nick Desaulniers
2019-08-19 18:03   ` Sedat Dilek
2019-08-12 21:50 ` [PATCH 16/16] compiler_attributes.h: add note about __section Nick Desaulniers
2019-08-19 18:01   ` Sedat Dilek
2019-08-12 21:50 ` Nick Desaulniers [this message]
2019-08-13 12:18   ` [PATCH 00/16] treewide: prefer __section from compiler_attributes.h Miguel Ojeda
2019-08-19 18:18   ` Sedat Dilek

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