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Rozycki" , linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, loongson-kernel@lists.loongnix.cn Subject: [PATCH v4 2/4] MIPS: Do not kill the task in die() if notify_die() returns NOTIFY_STOP Date: Sat, 19 Aug 2023 16:36:21 +0800 Message-Id: <1692434183-2054-3-git-send-email-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1692434183-2054-1-git-send-email-yangtiezhu@loongson.cn> References: <1692434183-2054-1-git-send-email-yangtiezhu@loongson.cn> X-CM-TRANSID: AQAAf8Cx_c4Hf+BkLDpeAA--.33957S4 X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBj93XoW7WFy8Zr4kGFWxXw4DJry3Jrc_yoW5JFy5pa 1qkasrGrWkGF4DXryDAF4DCrW3JrZ5K3y2kw10kw4F93ZIvryrXrs7GFWjvw1rtrW0qa4U WFWYvr18tFZ7AFcCm3ZEXasCq-sJn29KB7ZKAUJUUUUr529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUU90b4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r126r13M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4j6r4UJwAaw2AFwI0_Jrv_JF1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0c Ia020Ex4CE44I27wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jw0_ WrylYx0Ex4A2jsIE14v26r4j6F4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwI xGrwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwCFI7km07C267AKxVWU XVWUAwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67 kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY 6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0x vEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVj vjDU0xZFpf9x07jrPEfUUUUU= X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS 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: INBOX X-GMAIL-THRID: 1774765398910408875 X-GMAIL-MSGID: 1774765398910408875 If notify_die() returns NOTIFY_STOP, honor the return value from the handler chain invocation in die() and return without killing the task as, through a debugger, the fault may have been fixed. It makes sense even if ignoring the event will make the system unstable: by allowing access through a debugger it has been compromised already anyway. It makes our port consistent with x86, arm64, riscv and csky. Commit 20c0d2d44029 ("[PATCH] i386: pass proper trap numbers to die chain handlers") may be the earliest of similar changes. Link: https://lore.kernel.org/r/43DDF02E.76F0.0078.0@novell.com/ Signed-off-by: Tiezhu Yang --- arch/mips/include/asm/ptrace.h | 2 +- arch/mips/kernel/traps.c | 12 ++++++------ 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h index daf3cf2..aee8e0a 100644 --- a/arch/mips/include/asm/ptrace.h +++ b/arch/mips/include/asm/ptrace.h @@ -159,7 +159,7 @@ static inline long regs_return_value(struct pt_regs *regs) extern asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall); extern asmlinkage void syscall_trace_leave(struct pt_regs *regs); -extern void die(const char *, struct pt_regs *) __noreturn; +extern void die(const char *, struct pt_regs *); static inline void die_if_kernel(const char *str, struct pt_regs *regs) { diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index b1b68ce..8e528a8 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -391,16 +391,15 @@ void show_registers(struct pt_regs *regs) static DEFINE_RAW_SPINLOCK(die_lock); -void __noreturn die(const char *str, struct pt_regs *regs) +void die(const char *str, struct pt_regs *regs) { static int die_counter; - int sig = SIGSEGV; + int ret; oops_enter(); - if (notify_die(DIE_OOPS, str, regs, 0, current->thread.trap_nr, - SIGSEGV) == NOTIFY_STOP) - sig = 0; + ret = notify_die(DIE_OOPS, str, regs, 0, + current->thread.trap_nr, SIGSEGV); console_verbose(); raw_spin_lock_irq(&die_lock); @@ -422,7 +421,8 @@ void __noreturn die(const char *str, struct pt_regs *regs) if (regs && kexec_should_crash(current)) crash_kexec(regs); - make_task_dead(sig); + if (ret != NOTIFY_STOP) + make_task_dead(SIGSEGV); } extern struct exception_table_entry __start___dbe_table[];