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Howlett" Cc: Andrew Morton , maple-tree@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v2 1/2] maple_tree: Disable mas_wr_append() when other readers are possible In-Reply-To: <20230819004356.1454718-2-Liam.Howlett@oracle.com> (Liam R. Howlett's message of "Fri, 18 Aug 2023 20:43:55 -0400") References: <20230819004356.1454718-1-Liam.Howlett@oracle.com> <20230819004356.1454718-2-Liam.Howlett@oracle.com> X-Yow: Hmmm.. a CRIPPLED ACCOUNTANT with a FALAFEL sandwich is HIT by a TROLLEY-CAR.. Date: Wed, 30 Aug 2023 21:49:47 +0200 Message-ID: <87bkeotin8.fsf@igel.home> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Status: No, score=3.2 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL,RCVD_IN_SBL_CSS,RCVD_IN_SORBS_WEB,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Level: *** 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 This breaks booting on ppc32: Kernel attemptd to writ user page (1ff0) - exploit attempt? (uid: 0) BUG: Unable to handle kernel data access on write at 0x00001ff0 Faulting instruction address: 0xc0009554 Vector: 300 (Data Access) at [c0b09d10] pc: c0009554: do_softirq_own_stack+0x18/0x30 lr: c004f480: __irq_exit_rcu+0x70/0xc0 sp: c0b09dd0 msr: 1032 dar: 1ff0 dsisr: 42000000 current = 0xc0a08360 pid = 0, comm = swapper Linux version 6.5.0 ... enter ? for help [c0b09de0] c00ff480 __irq_exit_rcu+0x70/0xc0 [c0b09df0] c0005a98 Decrementer_virt+0x108/0x10c --- Exception: 900 (Decrementer) at c06cfa0c __schedule+0x4fc/0x510 [c0b09ec0] c06cf75c __schedule+0x1cc/0x510 (unreliable) [c0b09ef0] c06cfc90 __cond_resched+0x2c/0x54 [c0b09f00] c06d07f8 mutex_lock_killable+0x18/0x5c [c0b09f10] c013c404 pcpu_alloc+0x110/0x4dc [c0b09f70] c000cc34 alloc_descr.isra.18+0x48/0x144 [c0b09f90] c0988aa0 early_irq_init+0x64/0x8c [c0b09fa0] c097a5a4 start_kernel+0x5b4/0x7b0 [c0b09ff0] 00003dc0 mon> -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."