Re: [PATCH v5 OLK-5.10 6/7] arm64: send sig fault for user task when apei_claim_sea fails

On 2024/11/6 17:23, Wupeng Ma wrote:

From: Ma Wupeng mawupeng1@huawei.com

hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IB0OV7

---

During arm64_do_kernel_sea, kernel will panic if no info is reported to kernel since apei_claim_sea will fail. However, for user task, sig fault can be send to which can avoid kernel panic.

Signed-off-by: Ma Wupeng mawupeng1@huawei.com

arch/arm64/mm/fault.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-)

--- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -870,6 +870,9 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) static bool arm64_do_kernel_sea(void __user *addr, unsigned int esr, struct pt_regs *regs, int sig, int code) { + unsigned long orig_pc = regs->pc; + int err; + if (!IS_ENABLED(CONFIG_ARCH_HAS_COPY_MC)) return false;

@@ -879,13 +882,20 @@ static bool arm64_do_kernel_sea(void __user *addr, unsigned int esr, if (user_mode(regs)) return false;

- if (apei_claim_sea(regs) < 0) - return false; - if (!fixup_exception_mc(regs)) return false;

- if (current->flags & PF_KTHREAD) + err = apei_claim_sea(regs); + regs->pc = orig_pc; + + if (err) { + pr_emerg("apei claim sea failed. addr: %#lx, esr: %#x\n", + (unsigned long)addr, esr); + if (!current->mm) + return false; + } + + if (!current->mm) return true;

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index a2c61725c176..67f7ae98af56 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -729,6 +729,9 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) static bool arm64_do_kernel_sea(void __user *addr, unsigned int esr, struct pt_regs *regs, int sig, int code) {

• unsigned long pc;
• int err;
• if (!IS_ENABLED(CONFIG_ARCH_HAS_COPY_MC)) return false;

@@ -738,12 +741,20 @@ static bool arm64_do_kernel_sea(void __user *addr, unsigned int esr, if (user_mode(regs)) return false;

• if (apei_claim_sea(regs) < 0)

• return false;
  

• pc = regs->pc; if (!fixup_exception_mc(regs)) return false;

• err = apei_claim_sea(regs);

• if (err < 0) {

• pr_emerg("apei claim sea failed. addr: %#lx, esr: %#x\n",
  

• 	 (unsigned long)addr, esr);
  

• if (!current->mm) {
  

• 	regs->pc = pc;
  

• 	return false;
  

• }
  

• }

• if (current->flags & PF_KTHREAD) return true;