When one page is already hwpoisoned by AO action, process may not be
killed, the process mapping this page may make a syscall include this
page and result to trigger a VM_FAULT_HWPOISON fault, if it's in kernel
mode it may be fixed by fixup_exception. Current code will just return
error code to user process.
This is not sufficient, we should send a SIGBUS to the process and log
the info to console, as we can't trust the process will handle the error
correctly.
Suggested-by: Feng Yang <yangfe...@kingsoft.com>
Signed-off-by: Aili Yao <yaoa...@kingsoft.com>
---
arch/x86/mm/fault.c | 34 +++++++++++++++++++++++++++-------
1 file changed, 27 insertions(+), 7 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index f1f1b5a0956a..23095b94cf42 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -631,7 +631,7 @@ static void set_signal_archinfo(unsigned long address,
static noinline void
no_context(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, int signal, int si_code)
+ unsigned long address, int signal, int si_code, vm_fault_t fault)
{
struct task_struct *tsk = current;
unsigned long flags;
@@ -662,12 +662,32 @@ no_context(struct pt_regs *regs, unsigned long error_code,
* In this case we need to make sure we're not recursively
* faulting through the emulate_vsyscall() logic.
*/
+
+ if (IS_ENABLED(CONFIG_MEMORY_FAILURE) &&
+ fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
+ unsigned int lsb = 0;
+
+ pr_err("MCE: Killing %s:%d due to hardware memory
corruption fault at %lx\n",
+ current->comm, current->pid, address);
+
+ sanitize_error_code(address, &error_code);
+ set_signal_archinfo(address, error_code);
+
+ if (fault & VM_FAULT_HWPOISON_LARGE)
+ lsb =
hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
+ if (fault & VM_FAULT_HWPOISON)
+ lsb = PAGE_SHIFT;
+
+ force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address,
lsb);
+
+ return;
+ }
+
if (current->thread.sig_on_uaccess_err && signal) {
sanitize_error_code(address, &error_code);
set_signal_archinfo(address, error_code);
- /* XXX: hwpoison faults will set the wrong code. */
force_sig_fault(signal, si_code, (void __user
*)address);
}
@@ -836,7 +856,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long
error_code,
if (is_f00f_bug(regs, address))
return;
- no_context(regs, error_code, address, SIGSEGV, si_code);
+ no_context(regs, error_code, address, SIGSEGV, si_code, 0);
}
static noinline void
@@ -927,7 +947,7 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code,
unsigned long address,
{
/* Kernel mode? Handle exceptions or die: */
if (!(error_code & X86_PF_USER)) {
- no_context(regs, error_code, address, SIGBUS, BUS_ADRERR);
+ no_context(regs, error_code, address, SIGBUS, BUS_ADRERR,
fault);
return;
}
@@ -966,7 +986,7 @@ mm_fault_error(struct pt_regs *regs, unsigned long
error_code,
unsigned long address, vm_fault_t fault)
{
if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) {
- no_context(regs, error_code, address, 0, 0);
+ no_context(regs, error_code, address, 0, 0, 0);
return;
}
@@ -974,7 +994,7 @@ mm_fault_error(struct pt_regs *regs, unsigned long
error_code,
/* Kernel mode? Handle exceptions or die: */
if (!(error_code & X86_PF_USER)) {
no_context(regs, error_code, address,
- SIGSEGV, SEGV_MAPERR);
+ SIGSEGV, SEGV_MAPERR, 0);
return;
}
@@ -1396,7 +1416,7 @@ void do_user_addr_fault(struct pt_regs *regs,
if (fault_signal_pending(fault, regs)) {
if (!user_mode(regs))
no_context(regs, hw_error_code, address, SIGBUS,
- BUS_ADRERR);
+ BUS_ADRERR, 0);
return;
}
--
2.25.1
