diff mbox series

[05/10] microblaze: fix livelock in uaccess

Message ID Y9l0fUyGRidMrTqV@ZenIV (mailing list archive)
State Awaiting Upstream
Headers show
Series [01/10] alpha: fix livelock in uaccess | expand

Commit Message

Al Viro Jan. 31, 2023, 8:05 p.m. UTC
microblaze equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling"
If e.g. get_user() triggers a page fault and a fatal signal is caught, we might
end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything
to page tables.  In such case we must *not* return to the faulting insn -
that would repeat the entire thing without making any progress; what we need
instead is to treat that as failed (user) memory access.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
 arch/microblaze/mm/fault.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff mbox series


diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c
index 5c40c3ebe52f..32d9717039ba 100644
--- a/arch/microblaze/mm/fault.c
+++ b/arch/microblaze/mm/fault.c
@@ -219,8 +219,11 @@  void do_page_fault(struct pt_regs *regs, unsigned long address,
 	fault = handle_mm_fault(vma, address, flags, regs);
-	if (fault_signal_pending(fault, regs))
+	if (fault_signal_pending(fault, regs)) {
+		if (!user_mode(regs))
+			goto no_context;
+	}
 	/* The fault is fully completed (including releasing mmap lock) */
 	if (fault & VM_FAULT_COMPLETED)