Messages in this thread Patch in this message | | | From | Bryan Wu <> | Subject | [PATCH 25/32] Blackfin arch: fix signal handling bug | Date | Mon, 21 May 2007 18:09:33 +0800 |
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From: Bernd Schmidt <bernd.schmidt@analog.com>
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 <bernd.schmidt@analog.com> Signed-off-by: Bryan Wu <bryan.wu@analog.com> --- arch/blackfin/mach-common/entry.S | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S index e463733..7d03687 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; -- 1.5.1.2 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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