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McKenney" To: Sebastian Andrzej Siewior Cc: Vlastimil Babka , Marco Elver , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, sfr@canb.auug.org.au, longman@redhat.com, boqun.feng@gmail.com, cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org Subject: Re: [BUG] -next lockdep invalid wait context Message-ID: <186804c5-0ebd-4d38-b9ad-bfb74e39b353@paulmck-laptop> Reply-To: paulmck@kernel.org References: <41619255-cdc2-4573-a360-7794fc3614f7@paulmck-laptop> <66a745bb-d381-471c-aeee-3800a504f87d@paulmck-laptop> <20241031072136.JxDEfP5V@linutronix.de> <20241031075509.hCS9Amov@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241031075509.hCS9Amov@linutronix.de> X-Stat-Signature: q6dhz9y5dmsio9mdnwc84g43dc4gn4j7 X-Rspam-User: X-Rspamd-Queue-Id: 7F15340025 X-Rspamd-Server: rspam02 X-HE-Tag: 1730469237-569370 X-HE-Meta: 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 ib4E3yFd 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 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 Thu, Oct 31, 2024 at 08:55:09AM +0100, Sebastian Andrzej Siewior wrote: > On 2024-10-31 08:35:45 [+0100], Vlastimil Babka wrote: > > On 10/31/24 08:21, Sebastian Andrzej Siewior wrote: > > > On 2024-10-30 16:10:58 [-0700], Paul E. McKenney wrote: > > >> > > >> So I need to avoid calling kfree() within an smp_call_function() handler? > > > > > > Yes. No kmalloc()/ kfree() in IRQ context. > > > > However, isn't this the case that the rule is actually about hardirq context > > on RT, and most of these operations that are in IRQ context on !RT become > > the threaded interrupt context on RT, so they are actually fine? Or is smp > > call callback a hardirq context on RT and thus it really can't do those > > operations? > > interrupt handlers as of request_irq() are forced-threaded on RT so you > can do kmalloc()/ kfree() there. smp_call_function.*() on the other hand > are not threaded and invoked directly within the IRQ context. OK, thank you all for the explanation! I will fix using Boqun's suggestion of irq work, but avoiding the issue Boqun raises by invoking the irq-work handler from the smp_call_function() handler. It will be a few days before I get to this, so if there is a better way, please do not keep it a secret! Thanx, Paul