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ARM: 9221/1: traps: print un-hashed user pc on undefined instruction

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When user undefined instruction debug is enabled pc value is hashed like
kernel pointers for security reason. But the security benefit of this
hash is very limited because the code goes on to call __show_regs() that
prints the plain pointer value. pc is a user pointer anyway, so the
kernel does not leak anything. The only result is confusion about the
difference between the pc value on the first printed line, and the value
that __show_regs() prints.

Always print the plain value of pc.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Baruch Siach 2022-07-29 04:40:16 +01:00 committed by Russell King (Oracle)
parent b90cb10531
commit ee50036b25
1 changed files with 1 additions and 1 deletions
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2
arch/arm/kernel/traps.c
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@ -487,7 +487,7 @@ asmlinkage void do_undefinstr(struct pt_regs *regs)
die_sig:
#ifdef CONFIG_DEBUG_USER
if (user_debug & UDBG_UNDEFINED) {
pr_info("%s (%d): undefined instruction: pc=%p\n",
pr_info("%s (%d): undefined instruction: pc=%px\n",
current->comm, task_pid_nr(current), pc);
__show_regs(regs);
dump_instr(KERN_INFO, regs);