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From: Peter Zijlstra <peterz@infradead.org>
To: Marco Elver <elver@google.com>
Cc: Will Deacon <will@kernel.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH v5 00/18] Rework READ_ONCE() to improve codegen
Date: Thu, 14 May 2020 15:56:39 +0200	[thread overview]
Message-ID: <20200514135639.GA2978@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com>

On Thu, May 14, 2020 at 03:35:58PM +0200, Marco Elver wrote:

>   5. we should not break atomic_{read,set} for KCSAN. [Because of #1,
> we'd need to add data_race() around the arch-calls in
> atomic_{read,set}; or rely on Clang 11's -tsan-distinguish-volatile
> support (GCC 11 might get this as well).]

Putting the data_race() in atomic_{read,set} would 'break' any sanitized
user of arch_atomic_{read,set}(). Now it so happens there aren't any
such just now, but we need to be aware of that.

I'm thinking the volatile thing is the nicest solution, but yes, that'll
make us depend on 11 everything.


  parent reply	other threads:[~2020-05-14 13:56 UTC|newest]

Thread overview: 127+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-11 20:41 Will Deacon
2020-05-11 20:41 ` [PATCH v5 01/18] sparc32: mm: Fix argument checking in __srmmu_get_nocache() Will Deacon
2020-05-12 14:37   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 02/18] sparc32: mm: Restructure sparc32 MMU page-table layout Will Deacon
2020-05-12 14:37   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 03/18] sparc32: mm: Change pgtable_t type to pte_t * instead of struct page * Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 04/18] sparc32: mm: Reduce allocation size for PMD and PTE tables Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-17  0:00   ` [PATCH v5 04/18] " Guenter Roeck
2020-05-17  0:07     ` Guenter Roeck
2020-05-18  8:37       ` Will Deacon
2020-05-18  9:18         ` Mike Rapoport
2020-05-18  9:48         ` Guenter Roeck
2020-05-18 14:23           ` Mike Rapoport
2020-05-18 16:08             ` Guenter Roeck
2020-05-18 18:11               ` Ira Weiny
2020-05-18 18:14               ` Ira Weiny
2020-05-18 18:09             ` Guenter Roeck
2020-05-18 18:21               ` Ira Weiny
2020-05-18 19:15               ` Mike Rapoport
2020-05-19 16:40                 ` Guenter Roeck
2020-05-20 17:03         ` Mike Rapoport
2020-05-20 19:03           ` Guenter Roeck
2020-05-20 19:51             ` Mike Rapoport
2020-05-21 23:02               ` Guenter Roeck
2020-05-24 12:32                 ` Mike Rapoport
2020-05-24 14:01                   ` Guenter Roeck
2020-05-26 13:26                   ` Will Deacon
2020-05-26 14:01                     ` Will Deacon
2020-05-26 15:21                       ` Mike Rapoport
2020-05-26 16:18                       ` Guenter Roeck
2020-05-26 16:29                         ` Mike Rapoport
2020-05-26 17:15                           ` Guenter Roeck
2020-05-11 20:41 ` [PATCH v5 05/18] compiler/gcc: Raise minimum GCC version for kernel builds to 4.8 Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 06/18] netfilter: Avoid assigning 'const' pointer to non-const pointer Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 07/18] net: tls: " Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 08/18] fault_inject: Don't rely on "return value" from WRITE_ONCE() Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 09/18] arm64: csum: Disable KASAN for do_csum() Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 10/18] READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 11/18] READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 12/18] READ_ONCE: Drop pointer qualifiers when reading from scalar types Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 13/18] locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 14/18] arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 15/18] gcov: Remove old GCC 3.4 support Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 16/18] kcsan: Rework data_race() so that it can be used by READ_ONCE() Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-11 20:41 ` [PATCH v5 17/18] READ_ONCE: Use data_race() to avoid KCSAN instrumentation Will Deacon
2020-05-12  8:23   ` Peter Zijlstra
2020-05-12  9:49     ` Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-20 22:17     ` Borislav Petkov
2020-05-20 22:30       ` Marco Elver
2020-05-21  7:25         ` Borislav Petkov
2020-05-21  9:37           ` Marco Elver
2020-05-21  3:30       ` Nathan Chancellor
2020-05-22 16:08       ` [tip: locking/kcsan] compiler.h: Avoid nested statement expression in data_race() tip-bot2 for Marco Elver
2020-05-11 20:41 ` [PATCH v5 18/18] linux/compiler.h: Remove redundant '#else' Will Deacon
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Will Deacon
2020-05-12  8:18 ` [PATCH v5 00/18] Rework READ_ONCE() to improve codegen Peter Zijlstra
2020-05-12 17:53   ` Marco Elver
2020-05-12 18:55     ` Marco Elver
2020-05-12 19:07     ` Peter Zijlstra
2020-05-12 20:31       ` Marco Elver
2020-05-13 11:10         ` Peter Zijlstra
2020-05-13 11:14           ` Peter Zijlstra
2020-05-13 11:48           ` Marco Elver
2020-05-13 12:32             ` Peter Zijlstra
2020-05-13 12:40               ` Will Deacon
2020-05-13 13:15                 ` Marco Elver
2020-05-13 13:24                   ` Peter Zijlstra
2020-05-13 13:58                     ` Marco Elver
2020-05-14 11:21                       ` Peter Zijlstra
2020-05-14 11:24                         ` Peter Zijlstra
2020-05-14 11:35                         ` Peter Zijlstra
2020-05-14 12:01                         ` Will Deacon
2020-05-14 12:27                           ` Peter Zijlstra
2020-05-14 13:07                             ` Marco Elver
2020-05-14 13:14                               ` Peter Zijlstra
2020-05-14 12:20                         ` Peter Zijlstra
2020-05-14 14:13                       ` Peter Zijlstra
2020-05-14 14:20                         ` Marco Elver
2020-05-15  9:20                           ` Peter Zijlstra
2020-05-13 16:50                   ` Will Deacon
2020-05-13 17:32                     ` Marco Elver
2020-05-13 17:47                       ` Will Deacon
2020-05-13 18:54                         ` Marco Elver
2020-05-13 21:25                           ` Will Deacon
2020-05-14  7:31                             ` Marco Elver
2020-05-14 11:05                               ` Will Deacon
2020-05-14 13:35                                 ` Marco Elver
2020-05-14 13:47                                   ` Peter Zijlstra
2020-05-14 13:50                                   ` Peter Zijlstra
2020-05-14 13:56                                   ` Peter Zijlstra [this message]
2020-05-14 14:24                                   ` Peter Zijlstra
2020-05-14 15:09                                     ` Thomas Gleixner
2020-05-14 15:29                                       ` Marco Elver
2020-05-14 19:37                                         ` Thomas Gleixner
2020-05-15 13:55                                     ` David Laight
2020-05-15 14:04                                       ` Marco Elver
2020-05-15 14:07                                       ` Peter Zijlstra
2020-05-14 15:38                                   ` Paul E. McKenney
2020-05-22 16:08                                   ` [tip: locking/kcsan] kcsan: Restrict supported compilers tip-bot2 for Marco Elver
2020-06-03 18:52                                 ` [PATCH v5 00/18] Rework READ_ONCE() to improve codegen Borislav Petkov
2020-06-03 19:23                                   ` Marco Elver
2020-06-03 22:05                                     ` Borislav Petkov
2020-06-08 17:32                                     ` Martin Liška
2020-06-08 19:56                                       ` Marco Elver
2020-06-09 11:55                                         ` Martin Liška
2020-06-09 12:36                                           ` Martin Liška
2020-06-09 13:45                                             ` Marco Elver
2020-05-22 16:08                           ` [tip: locking/kcsan] kcsan: Remove 'noinline' from __no_kcsan_or_inline tip-bot2 for Marco Elver
2020-05-13 13:21                 ` [PATCH v5 00/18] Rework READ_ONCE() to improve codegen David Laight
2020-05-13 16:32                   ` Thomas Gleixner
2020-05-12 21:14       ` Will Deacon
2020-05-12 22:00         ` Marco Elver

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