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b=aJNb3rG9eLyETc+c7dCYcxs8r8eBXcRmz0vVg8vuKZW2GoHqqFbVgBbrVrjq9Dysp WTN60mY3CklTkxWRllzkM7NyNddnqX0/Gbk76qbzyp8wTw6rWxy+W9pGwrqyNJQ7Jg tCYkIkvGdY83GQvSDv4miLSw7Aicx8OR2sy0Vo2GQIwntQXfT9n7YyhnZr2ECabXTs ZTyOI7GATKJNiaOtKWAk4JH1C8JvH3iusGCdCP7yPGxxOhaO/c1q0+4hm2DsPJoGGT B/UTvqYPlB1eCwgQ5D7QlRL4dWvxb6jGXRe4b6V7Wwv3UgBlPriRN2fX+5nm4PsXUS mwrDtr4syMDGg== From: Pratyush Yadav To: Pasha Tatashin Cc: rppt@kernel.org, sourabhjain@linux.ibm.com, jbouron@amazon.com, akpm@linux-foundation.org, linux-mm@kvack.org, bhe@redhat.com, linux-kernel@vger.kernel.org, dan.carpenter@linaro.org, rafael.j.wysocki@intel.com, piliu@redhat.com, kexec@lists.infradead.org, pratyush@kernel.org, graf@amazon.com, changyuanl@google.com, mario.limonciello@amd.com Subject: Re: [PATCH v2 3/3] liveupdate: block outgoing session mutations In-Reply-To: <20260506182039.2623553-8-pasha.tatashin@soleen.com> (Pasha Tatashin's message of "Wed, 6 May 2026 14:20:43 -0400") References: <20260506182039.2623553-5-pasha.tatashin@soleen.com> <20260506182039.2623553-8-pasha.tatashin@soleen.com> Date: Mon, 11 May 2026 13:03:34 +0200 Message-ID: <2vxzv7cucint.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C2ECD80007 X-Rspam-User: X-Stat-Signature: 44mm47kik6j9o5ttr9uyqy1zds63c97r X-HE-Tag: 1778497419-12029 X-HE-Meta: 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 WiEKxmWB PTXxE1SsMTsJdg7JvW72Mggpe6qBHfoDjFwVKDwuKvjGjuNJK4VK1o9mLLymr0Aza5SCSTZ8dXadlNZszbp4WWoTCy3shGJNqot7Jth8cTSbbwjkmMjMdZanIv8n8ruYg3YyOLWU0JUxnDUGPuGwlSXayCmXYzRKaLwsjjJA2U7qDQfrSCdYuEH1KqjzSsnyoOwZHXiZSD0TwE0qtp810EGjTRFp9bTe8H4/Rpln5aUSwOaE5UTl04tSYL0JrNR9GFFN08kAjWyWVace3MG2RVXFLeg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, May 06 2026, Pasha Tatashin wrote: > During the reboot() syscall, user processes may still be running > concurrently and attempting to mutate sessions (e.g., adding files or > closing sessions). To prevent this, hold the session header's rwsem and > each session's mutex indefinitely on successful serialization. > > If serialization succeeds, these locks will never be released as the > system transitions to the new kernel, effectively blocking any > concurrent task attempting to modify or release a session. If > liveupdate_reboot() fails, the locks are released in the error path, > allowing normal operation to resume. > > Fixes: 0153094d03df ("liveupdate: luo_session: add sessions support") > Reported-by: Oskar Gerlicz Kowalczuk > Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav (Google) [...] -- Regards, Pratyush Yadav