linux/include
Richard Weinberger 9d8a765211 kernel/signal.c: unexport sigsuspend()
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: 68f3f16d9a ("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>
Cc: <stable@vger.kernel.org>	[3.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-20 16:17:32 -08:00
..
acpi Merge branch 'acpi-pci' 2015-11-07 01:30:10 +01:00
asm-generic h8300 update for v4.4 2015-11-12 15:26:39 -08:00
clocksource
crypto Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2015-11-05 15:32:38 -08:00
drm drm/atomic: add a drm_atomic_clean_old_fb helper. 2015-11-17 13:02:14 +02:00
dt-bindings ARM: DT updates for v4.4 2015-11-10 15:06:26 -08:00
keys KEYS: Merge the type-specific data with the payload data 2015-10-21 15:18:36 +01:00
kvm s390: A bunch of fixes and optimizations for interrupt and time 2015-11-05 16:26:26 -08:00
linux kernel/signal.c: unexport sigsuspend() 2015-11-20 16:17:32 -08:00
math-emu
media [media] v4l2: add support for SDR transmitter 2015-10-20 15:40:50 -02:00
memory
misc
net net: switchdev: fix return code of fdb_dump stub 2015-11-16 15:24:37 -05:00
pcmcia
ras
rdma IB/core, cma: Make __attribute_const__ declarations sparse-friendly 2015-10-30 17:57:49 -04:00
rxrpc
scsi scsi: use host wide tags by default 2015-11-09 17:11:57 -08:00
soc ARM: SoC driver updates for v4.4 2015-11-10 15:00:03 -08:00
sound ALSA: Constify ratden/ratnum constraints 2015-10-28 11:42:22 +01:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2015-11-13 20:04:17 -08:00
trace Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2015-11-11 09:03:01 -08:00
uapi VFIO updates for v4.4-rc1 2015-11-13 17:05:32 -08:00
video drm/exynos/decon5433: add support for DECON-TV 2015-11-03 11:46:37 +09:00
xen xen/grant-table: Add an helper to iterate over a specific number of grants 2015-10-23 14:20:46 +01:00
Kbuild