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b=EiOv9hi4CjxJHl05f87A+5TVs7u/sO2FITeu5sj53f+LQoZl+i5IpF4Or7APrW4NS BDbebIaH4c6oQ0dDR6iurDyKo6MwLpPPbsmaPaI+czl0OL8JmYbZjtn2qbWH+p+GBA 7ywYP0UPRILvaqhVLWKWFtm68ZsdV0NKRdDDTHKKXx9tWl09AKcX8lLd+hiemrVR6G 0mY4faQ4ShH37ezOapTDk8NaCN1hIk9wODkRH4FOtDq0dq/XPt2UYl4yP1p0Zx15so H7RTyBsccQioWHEcs1sQ3n+lQzJ1y8SWBPjuibORjlMGDmeixuHoGZ4oROZdYpLUj9 ZVlp80xtcNVFA== Date: Sun, 22 Mar 2026 13:01:35 +0200 From: Mike Rapoport To: Hubert Mazur Cc: Andrew Morton , Greg Kroah-Hartman , Stanislaw Kardach , Michal Krawczyk , Slawomir Rosek , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4] mm/execmem: Make the populate and alloc atomic Message-ID: References: <20260320075723.779985-1-hmazur@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260320075723.779985-1-hmazur@google.com> X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: DF20E1C0018 X-Stat-Signature: 1dcgus7nh44gaqaoz8ussbjbrm5qsgwp X-Rspam-User: X-HE-Tag: 1774177302-54960 X-HE-Meta: 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Mar 20, 2026 at 07:57:23AM +0000, Hubert Mazur wrote: > When a block of memory is requested from the execmem manager it tries > to find a suitable fragment by traversing the free_areas. In case > there is no such block, a new memory area is added to the free_areas > and then allocated to the caller by traversing the free_area tree again. > > The above operations of allocation and tree traversal are not atomic > hence another request may consume this newly allocated memory block > which results in the allocation failure for the original request. > Such occurrence can be spotted on devices running the 6.18 kernel > during the parallel modules loading. > > To mitigate such resource races execute the cache population and > allocation operations under one mutex lock. > > Signed-off-by: Hubert Mazur Reviewed-by: Mike Rapoport (Microsoft) > --- -- Sincerely yours, Mike.