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b=MMrOLjp+6H6s9aB2GTXCpXJrrtvKEx7+S3j8mPsUTpnZaLl8ktld7Z32qdym2ASPx frVQTMUDdwtE7ZKuC3I/KpYh/sCnRbRg9lIS0rJsGOj/dhEegWqJo/27SfdtDhPODg MbiB4MchG/xAmGKIEGIk7P9JbTGMW1UHka/DNp3w= Date: Thu, 21 Nov 2024 22:28:09 -0800 From: Andrew Morton To: Jared Kangas Cc: ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kasan: make report_lock a raw spinlock Message-Id: <20241121222809.4b53e070a943e100bb6f7ba0@linux-foundation.org> In-Reply-To: <20241119210234.1602529-1-jkangas@redhat.com> References: <20241119210234.1602529-1-jkangas@redhat.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: AA9E11C0007 X-Stat-Signature: 4cqwo5azotkmm69brd1h6eo316u6dynh X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1732256796-685945 X-HE-Meta: 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 SLk8Iyb4 MRJ/Yl7DZIoLke/xexKOuu9cr6UHtpo1WfCuQvSEXkz1ewYDFcdptgY7f1T957VSDpftNmtf/XzEGjCe83e2ah7xZA3KLvNJDFMrbfXS/PwmVa+wwphctR/+dFyN10h1oxmQ6iR1y7DlGNWpnc4u1TUTbvMeR6ypnB8yZ4be/miX/9Hg232h3Nu5/RoqsUENAsSpanYHzK3RH21bnPlDIhIhbJbMaZ2MdErYOqXvx6wjkiWGQIqMxPKJVOQcuWiRnte6pXV0Z1FUzbvEqb9hXLx0znGpToq2+wIE+YMKGLKfAMQQX8PUnyzM0OjADZAm/xme0hniTXlcXqRBp7aFN7BsYJaeLFxMqZXZvjZdSVjkO7Xj3fJErI3fpoCJvociKtDmAg8MymTcf39xxoyVMBlZ/cPPJKImaJ+gf X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 19 Nov 2024 13:02:34 -0800 Jared Kangas wrote: > If PREEMPT_RT is enabled, report_lock is a sleeping spinlock and must > not be locked when IRQs are disabled. However, KASAN reports may be > triggered in such contexts. For example: > > char *s = kzalloc(1, GFP_KERNEL); > kfree(s); > local_irq_disable(); > char c = *s; /* KASAN report here leads to spin_lock() */ > local_irq_enable(); > > Make report_spinlock a raw spinlock to prevent rescheduling when > PREEMPT_RT is enabled. So I assume we want this backported into 6.12.x? If so, please help us identify a suitable Fixes: commit.