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McKenney" To: torvalds@linux-foundation.org Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, rcu@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org Subject: [GIT PULL] Keep synchronize_rcu() from enabling irqs in early boot Message-ID: <20221024165421.GA1246679@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org MIME-Version: 1.0 Content-Disposition: inline X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,RCVD_IN_DNSWL_HI,SPF_HELO_NONE, SPF_PASS,URG_BIZ autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1747599367364178053?= X-GMAIL-MSGID: =?utf-8?q?1747599367364178053?= Hello, Linus, This pull request fixes a merge-window regression noted by Steve Rostedt. The following changes since commit 9abf2313adc1ca1b6180c508c25f22f9395cc780: Linux 6.1-rc1 (2022-10-16 15:36:24 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git tags/rcu-urgent.2022.10.20a for you to fetch changes up to 31d8aaa87fcef1be5932f3813ea369e21bd3b11d: rcu: Keep synchronize_rcu() from enabling irqs in early boot (2022-10-20 15:34:49 -0700) ---------------------------------------------------------------- Urgent RCU pull request for v6.1 This pull request contains a commit that fixes bf95b2bc3e42 ("rcu: Switch polled grace-period APIs to ->gp_seq_polled"), which could incorrectly leave interrupts enabled after an early-boot call to synchronize_rcu(). Such synchronize_rcu() calls must acquire leaf rcu_node locks in order to properly interact with polled grace periods, but the code did not take into account the possibility of synchronize_rcu() being invoked from the portion of the boot sequence during which interrupts are disabled. This commit therefore switches the lock acquisition and release from irq to irqsave/irqrestore. ---------------------------------------------------------------- Paul E. McKenney (1): rcu: Keep synchronize_rcu() from enabling irqs in early boot kernel/rcu/tree.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)