[PATCH] powerpc:Don't print raw EIP/LR hex values in dump_stack() and show_regs()

From: Xiaoming Ni
Date: Sun Dec 20 2020 - 22:28:56 EST


Since the commit 2b0e86cc5de6 ("powerpc/fsl_booke/32: implement KASLR
infrastructure"), the powerpc system is ready to support KASLR.
To reduces the risk of invalidating address randomization, don't print the
EIP/LR hex values in dump_stack() and show_regs().

This patch follows x86 and arm64's lead:
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@xxxxxxxxxx>
---
arch/powerpc/kernel/process.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index a66f435dabbf..913cf1ea702e 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1455,8 +1455,8 @@ static void __show_regs(struct pt_regs *regs)
{
int i, trap;

- printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
- regs->nip, regs->link, regs->ctr);
+ printk("NIP: %pS LR: %pS CTR: "REG"\n",
+ (void *)regs->nip, (void *)regs->link, regs->ctr);
printk("REGS: %px TRAP: %04lx %s (%s)\n",
regs, regs->trap, print_tainted(), init_utsname()->release);
printk("MSR: "REG" ", regs->msr);
@@ -1493,8 +1493,8 @@ static void __show_regs(struct pt_regs *regs)
* above info out without failing
*/
if (IS_ENABLED(CONFIG_KALLSYMS)) {
- printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
- printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
+ printk("NIP %pS\n", (void *)regs->nip);
+ printk("LR %pS\n", (void *)regs->link);
}
}

@@ -2160,8 +2160,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack,
newsp = stack[0];
ip = stack[STACK_FRAME_LR_SAVE];
if (!firstframe || ip != lr) {
- printk("%s["REG"] ["REG"] %pS",
- loglvl, sp, ip, (void *)ip);
+ printk("%s ["REG"] %pS",
+ loglvl, sp, (void *)ip);
ret_addr = ftrace_graph_ret_addr(current,
&ftrace_idx, ip, stack);
if (ret_addr != ip)
--
2.27.0