From c824498db47285aeff430c007685a193b673c949 Mon Sep 17 00:00:00 2001 From: Bernd Schmidt Date: Mon, 21 May 2007 18:09:33 +0800 Subject: [PATCH] Blackfin arch: fix signal handling bug There's a forum thread at https://blackfin.uclinux.org/gf/project/uclinux-dist/forum/?action=ForumBrowse&_forum_action=MessageReply&message_id=24741 which has a testcase involving signal handling that crashes quite readily. Inspecting the code I believe what happens is that signal handling can become confused when it is invoked on return from an interrupt, if the contents of P0 and R0 at the time of the interrupt happen to be such that P0 is larger than zero (indicating to the signal code that we're in a syscall), and R0 happens to have a value of something like -EINTR or -ERESTARTSYS. Fixed by setting orig_p0 to -1 if we're returning from an interrupt. The testcase now seems to run without problems. Signed-off-by: Bernd Schmidt Signed-off-by: Bryan Wu Signed-off-by: Linus Torvalds --- arch/blackfin/mach-common/entry.S | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S index e463733f5c77..7d0368772cda 100644 --- a/arch/blackfin/mach-common/entry.S +++ b/arch/blackfin/mach-common/entry.S @@ -712,6 +712,11 @@ _schedule_and_signal_from_int: p1.h = _evt_system_call; [p0] = p1; csync; + + /* Set orig_p0 to -1 to indicate this isn't the end of a syscall. */ + r0 = -1 (x); + [sp + PT_ORIG_P0] = r0; + p1 = rets; [sp + PT_RESERVED] = p1; -- 2.30.2