Messages in this thread Patch in this message | | | From | Florian Fainelli <> | Subject | [PATCH v2] ARM: mm: Facilitate debugging CONFIG_KUSER_HELPERS disabled | Date | Thu, 25 Oct 2018 12:01:08 -0700 |
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Some software such as perf makes unconditional use of the special [vectors] page which is only provided when CONFIG_KUSER_HELPERS is enabled in the kernel.
Facilitate the debugging of such situations by printing a debug message to the kernel log showing the task name and the faulting address.
Suggested-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> --- arch/arm/mm/fault.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index f4ea4c62c613..58f69fa07df9 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -173,6 +173,12 @@ __do_user_fault(struct task_struct *tsk, unsigned long addr, show_regs(regs); } #endif +#ifndef CONFIG_KUSER_HELPERS + if ((sig == SIGSEGV) && ((addr & PAGE_MASK) == 0xffff0000)) + printk_ratelimited(KERN_DEBUG + "%s: CONFIG_KUSER_HELPERS disabled at 0x%08lx\n", + tsk->comm, addr); +#endif tsk->thread.address = addr; tsk->thread.error_code = fsr; -- 2.17.1
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