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Subjectping //Re: [PATCH v2] arm:traps: Don't print stack or raw PC/LR hex values in backtraces
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On 2020/10/16 10:31, Xiaoming Ni wrote:
> Printing raw pointer values in backtraces has potential security
> implications and are of questionable value anyway.
>
> This patch follows x86 and arm64's lead and removes the "Exception stack:"
> dump from kernel backtraces:
> commit a25ffd3a6302a6 ("arm64: traps: Don't print stack or raw
> PC/LR values in backtraces")
> commit bb5e5ce545f203 ("x86/dumpstack: Remove kernel text
> addresses from stack dump")
>
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>
> -------
> v2:
> Delete [<hex numbers>] from the stack according to the email discussion
> in patch V1, Other information processing will be discussed in subsequent
> patches.
>
> v1: https://lore.kernel.org/lkml/20201009075957.110017-1-nixiaoming@huawei.com/
> 1. Don't print stack or raw PC/LR hex values in backtraces
> 2. Don't print stack mem in backtraces
> 3. if (!panic_on_oops), Don't print stack mem in __die()
> ---
> arch/arm/kernel/process.c | 3 +--
> arch/arm/kernel/traps.c | 4 ++--
> 2 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
> index 8e6ace03e960..71c9e5597d39 100644
> --- a/arch/arm/kernel/process.c
> +++ b/arch/arm/kernel/process.c
> @@ -121,8 +121,7 @@ void __show_regs(struct pt_regs *regs)
>
> printk("PC is at %pS\n", (void *)instruction_pointer(regs));
> printk("LR is at %pS\n", (void *)regs->ARM_lr);
> - printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
> - regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
> + printk("psr: %08lx\n", regs->ARM_cpsr);
> printk("sp : %08lx ip : %08lx fp : %08lx\n",
> regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
> printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
> diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
> index 17d5a785df28..911bbf164875 100644
> --- a/arch/arm/kernel/traps.c
> +++ b/arch/arm/kernel/traps.c
> @@ -68,8 +68,8 @@ void dump_backtrace_entry(unsigned long where, unsigned long from,
> unsigned long end = frame + 4 + sizeof(struct pt_regs);
>
> #ifdef CONFIG_KALLSYMS
> - printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n",
> - loglvl, where, (void *)where, from, (void *)from);
> + printk("%s (%ps) from (%pS)\n",
> + loglvl, (void *)where, (void *)from);
> #else
> printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",
> loglvl, where, from);
>

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