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Commit | Line | Data |
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d33cec38 GKH |
1 | From 1e6f5440a6814d28c32d347f338bfef68bc3e69d Mon Sep 17 00:00:00 2001 |
2 | From: Will Deacon <will.deacon@arm.com> | |
3 | Date: Mon, 8 Apr 2019 17:56:34 +0100 | |
4 | Subject: arm64: backtrace: Don't bother trying to unwind the userspace stack | |
5 | ||
6 | From: Will Deacon <will.deacon@arm.com> | |
7 | ||
8 | commit 1e6f5440a6814d28c32d347f338bfef68bc3e69d upstream. | |
9 | ||
10 | Calling dump_backtrace() with a pt_regs argument corresponding to | |
11 | userspace doesn't make any sense and our unwinder will simply print | |
12 | "Call trace:" before unwinding the stack looking for user frames. | |
13 | ||
14 | Rather than go through this song and dance, just return early if we're | |
15 | passed a user register state. | |
16 | ||
17 | Cc: <stable@vger.kernel.org> | |
18 | Fixes: 1149aad10b1e ("arm64: Add dump_backtrace() in show_regs") | |
19 | Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com> | |
20 | Signed-off-by: Will Deacon <will.deacon@arm.com> | |
21 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
22 | ||
23 | --- | |
24 | arch/arm64/kernel/traps.c | 15 +++++++++------ | |
25 | 1 file changed, 9 insertions(+), 6 deletions(-) | |
26 | ||
27 | --- a/arch/arm64/kernel/traps.c | |
28 | +++ b/arch/arm64/kernel/traps.c | |
29 | @@ -101,10 +101,16 @@ static void dump_instr(const char *lvl, | |
30 | void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) | |
31 | { | |
32 | struct stackframe frame; | |
33 | - int skip; | |
34 | + int skip = 0; | |
35 | ||
36 | pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); | |
37 | ||
38 | + if (regs) { | |
39 | + if (user_mode(regs)) | |
40 | + return; | |
41 | + skip = 1; | |
42 | + } | |
43 | + | |
44 | if (!tsk) | |
45 | tsk = current; | |
46 | ||
47 | @@ -125,7 +131,6 @@ void dump_backtrace(struct pt_regs *regs | |
48 | frame.graph = tsk->curr_ret_stack; | |
49 | #endif | |
50 | ||
51 | - skip = !!regs; | |
52 | printk("Call trace:\n"); | |
53 | do { | |
54 | /* skip until specified stack frame */ | |
55 | @@ -175,15 +180,13 @@ static int __die(const char *str, int er | |
56 | return ret; | |
57 | ||
58 | print_modules(); | |
59 | - __show_regs(regs); | |
60 | pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", | |
61 | TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), | |
62 | end_of_stack(tsk)); | |
63 | + show_regs(regs); | |
64 | ||
65 | - if (!user_mode(regs)) { | |
66 | - dump_backtrace(regs, tsk); | |
67 | + if (!user_mode(regs)) | |
68 | dump_instr(KERN_EMERG, regs); | |
69 | - } | |
70 | ||
71 | return ret; | |
72 | } |