| Message ID | 1450133244-9185-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/include/linux/signal.h b/include/linux/signal.h index ab1e039..92557bb 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -239,7 +239,6 @@ extern int sigprocmask(int, sigset_t *, sigset_t *); extern void set_current_blocked(sigset_t *); extern void __set_current_blocked(const sigset_t *); extern int show_unhandled_signals; -extern int sigsuspend(sigset_t *); struct sigaction { #ifndef __ARCH_HAS_IRIX_SIGACTION diff --git a/kernel/signal.c b/kernel/signal.c index 16a3052..c4dc622 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3558,7 +3558,7 @@ SYSCALL_DEFINE0(pause) #endif -int sigsuspend(sigset_t *set) +static int sigsuspend(sigset_t *set) { current->saved_sigmask = current->blocked; set_current_blocked(set);
This is a note to let you know that I have just added a patch titled kernel/signal.c: unexport sigsuspend() to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt12. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 608699d4b58eef1deea43ec9e076e32ab9b4384d Mon Sep 17 00:00:00 2001 From: Richard Weinberger <richard@nod.at> Date: Fri, 20 Nov 2015 15:57:21 -0800 Subject: kernel/signal.c: unexport sigsuspend() commit 9d8a765211335cfdad464b90fb19f546af5706ae upstream. sigsuspend() is nowhere used except in signal.c itself, so we can mark it static do not pollute the global namespace. But this patch is more than a boring cleanup patch, it fixes a real issue on UserModeLinux. UML has a special console driver to display ttys using xterm, or other terminal emulators, on the host side. Vegard reported that sometimes UML is unable to spawn a xterm and he's facing the following warning: WARNING: CPU: 0 PID: 908 at include/linux/thread_info.h:128 sigsuspend+0xab/0xc0() It turned out that this warning makes absolutely no sense as the UML xterm code calls sigsuspend() on the host side, at least it tries. But as the kernel itself offers a sigsuspend() symbol the linker choose this one instead of the glibc wrapper. Interestingly this code used to work since ever but always blocked signals on the wrong side. Some recent kernel change made the WARN_ON() trigger and uncovered the bug. It is a wonderful example of how much works by chance on computers. :-) Fixes: 68f3f16d9ad0f1 ("new helper: sigsuspend()") Signed-off-by: Richard Weinberger <richard@nod.at> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Tested-by: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- include/linux/signal.h | 1 - kernel/signal.c | 2 +- 2 files changed, 1 insertion(+), 2 deletions(-) -- 1.9.1