From: "Nicholas Piggin" <npiggin@gmail.com>
To: "Rohan McLure" <rmclure@linux.ibm.com>, <linuxppc-dev@lists.ozlabs.org>
Cc: gautam@linux.ibm.com, arnd@arndb.de
Subject: Re: [PATCH v2 06/11] powerpc: powernv: Fix KCSAN datarace warnings on idle_state contention
Date: Mon, 15 May 2023 15:50:55 +1000 [thread overview]
Message-ID: <CSMM7IOP142I.1M5WWIXODLFUE@wheely> (raw)
In-Reply-To: <20230510033117.1395895-7-rmclure@linux.ibm.com>
On Wed May 10, 2023 at 1:31 PM AEST, Rohan McLure wrote:
> The idle_state entry in the PACA on PowerNV features a bit which is
> atomically tested and set through ldarx/stdcx. to be used as a spinlock.
> This lock then guards access to other bit fields of idle_state. KCSAN
> cannot differentiate between any of these bitfield accesses as they all
> are implemented by 8-byte store/load instructions, thus cores contending
> on the bit-lock appear to data race with modifications to idle_state.
>
> Separate the bit-lock entry from the data guarded by the lock to avoid
> the possibility of data races being detected by KCSAN.
>
> Suggested-by: Nicholas Piggin <npiggin@gmail.com>
> Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
next prev parent reply other threads:[~2023-05-15 5:51 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-10 3:31 [PATCH v2 00/11] powerpc: KCSAN fix warnings and mark accesses Rohan McLure
2023-05-10 3:31 ` [PATCH v2 01/11] powerpc: qspinlock: Mark accesses to qnode lock checks Rohan McLure
2023-05-10 3:31 ` [PATCH v2 02/11] powerpc: qspinlock: Enforce qnode writes prior to publishing to queue Rohan McLure
2023-05-15 5:46 ` Nicholas Piggin
2023-05-10 3:31 ` [PATCH v2 03/11] asm-generic/mmiowb: Mark accesses to fix KCSAN warnings Rohan McLure
2023-05-12 2:20 ` Michael Ellerman
2023-05-15 5:48 ` Nicholas Piggin
2023-05-23 0:28 ` Rohan McLure
2023-05-23 0:36 ` Rohan McLure
2023-05-10 3:31 ` [PATCH v2 04/11] powerpc: Mark [h]ssr_valid accesses in check_return_regs_valid Rohan McLure
2023-05-10 3:31 ` [PATCH v2 05/11] powerpc: Mark accesses to power_save callback in arch_cpu_idle Rohan McLure
2023-05-15 5:50 ` Nicholas Piggin
2023-05-16 2:27 ` Rohan McLure
2023-05-10 3:31 ` [PATCH v2 06/11] powerpc: powernv: Fix KCSAN datarace warnings on idle_state contention Rohan McLure
2023-05-15 5:50 ` Nicholas Piggin [this message]
2023-05-10 3:31 ` [PATCH v2 07/11] powerpc: Annotate accesses to ipi message flags Rohan McLure
2023-05-15 5:51 ` Nicholas Piggin
2023-05-10 3:31 ` [PATCH v2 08/11] powerpc: Mark writes registering ipi to host cpu through kvm and polling Rohan McLure
2023-05-15 5:53 ` Nicholas Piggin
2023-05-15 22:19 ` Rohan McLure
2023-05-10 3:31 ` [PATCH v2 09/11] powerpc: powernv: Annotate data races in opal events Rohan McLure
2023-05-10 3:31 ` [PATCH v2 10/11] powerpc: powernv: Annotate asynchronous access to opal tokens Rohan McLure
2023-05-10 3:31 ` [PATCH v2 11/11] powerpc: Mark asynchronous accesses to irq_data Rohan McLure
2023-07-03 5:26 ` (subset) [PATCH v2 00/11] powerpc: KCSAN fix warnings and mark accesses Michael Ellerman
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