From: Will Deacon <will.deacon@arm.com> To: linux-arm-kernel@lists.infradead.org Cc: mark.rutland@arm.com, Will Deacon <will.deacon@arm.com>, stable@vger.kernel.org Subject: [PATCH] arm64: backtrace: Don't bother trying to unwind the userspace stack Date: Mon, 8 Apr 2019 18:12:37 +0100 [thread overview] Message-ID: <20190408171237.12045-1-will.deacon@arm.com> (raw) Calling dump_backtrace() with a pt_regs argument corresponding to userspace doesn't make any sense and our unwinder will simply print "Call trace:" before unwinding the stack looking for user frames. Rather than go through this song and dance, just return early if we're passed a user register state. Cc: <stable@vger.kernel.org> Fixes: 1149aad10b1e ("arm64: Add dump_backtrace() in show_regs") Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/arm64/kernel/traps.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 8ad119c3f665..29755989f616 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -102,10 +102,16 @@ static void dump_instr(const char *lvl, struct pt_regs *regs) void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) { struct stackframe frame; - int skip; + int skip = 0; pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); + if (regs) { + if (user_mode(regs)) + return; + skip = 1; + } + if (!tsk) tsk = current; @@ -126,7 +132,6 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) frame.graph = 0; #endif - skip = !!regs; printk("Call trace:\n"); do { /* skip until specified stack frame */ @@ -176,15 +181,13 @@ static int __die(const char *str, int err, struct pt_regs *regs) return ret; print_modules(); - __show_regs(regs); pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); + show_regs(regs); - if (!user_mode(regs)) { - dump_backtrace(regs, tsk); + if (!user_mode(regs)) dump_instr(KERN_EMERG, regs); - } return ret; } -- 2.11.0
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will.deacon@arm.com> To: linux-arm-kernel@lists.infradead.org Cc: mark.rutland@arm.com, Will Deacon <will.deacon@arm.com>, stable@vger.kernel.org Subject: [PATCH] arm64: backtrace: Don't bother trying to unwind the userspace stack Date: Mon, 8 Apr 2019 18:12:37 +0100 [thread overview] Message-ID: <20190408171237.12045-1-will.deacon@arm.com> (raw) Calling dump_backtrace() with a pt_regs argument corresponding to userspace doesn't make any sense and our unwinder will simply print "Call trace:" before unwinding the stack looking for user frames. Rather than go through this song and dance, just return early if we're passed a user register state. Cc: <stable@vger.kernel.org> Fixes: 1149aad10b1e ("arm64: Add dump_backtrace() in show_regs") Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/arm64/kernel/traps.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 8ad119c3f665..29755989f616 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -102,10 +102,16 @@ static void dump_instr(const char *lvl, struct pt_regs *regs) void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) { struct stackframe frame; - int skip; + int skip = 0; pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); + if (regs) { + if (user_mode(regs)) + return; + skip = 1; + } + if (!tsk) tsk = current; @@ -126,7 +132,6 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) frame.graph = 0; #endif - skip = !!regs; printk("Call trace:\n"); do { /* skip until specified stack frame */ @@ -176,15 +181,13 @@ static int __die(const char *str, int err, struct pt_regs *regs) return ret; print_modules(); - __show_regs(regs); pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); + show_regs(regs); - if (!user_mode(regs)) { - dump_backtrace(regs, tsk); + if (!user_mode(regs)) dump_instr(KERN_EMERG, regs); - } return ret; } -- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2019-04-08 17:12 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-08 17:12 Will Deacon [this message] 2019-04-08 17:12 ` [PATCH] arm64: backtrace: Don't bother trying to unwind the userspace stack Will Deacon
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