Mikulas Patocka 629bfb9f6b alpha: fix crash if pthread_create races with signal delivery ... commit 21ffceda1c upstream. On alpha, a process will crash if it attempts to start a thread and a signal is delivered at the same time. The crash can be reproduced with this program: https://cygwin.com/ml/cygwin/2014-11/msg00473.html The reason for the crash is this: * we call the clone syscall * we go to the function copy_process * copy process calls copy_thread_tls, it is a wrapper around copy_thread * copy_thread sets the tls pointer: childti->pcb.unique = regs->r20 * copy_thread sets regs->r20 to zero * we go back to copy_process * copy process checks "if (signal_pending(current))" and returns -ERESTARTNOINTR * the clone syscall is restarted, but this time, regs->r20 is zero, so the new thread is created with zero tls pointer * the new thread crashes in start_thread when attempting to access tls The comment in the code says that setting the register r20 is some compatibility with OSF/1. But OSF/1 doesn't use the CLONE_SETTLS flag, so we don't have to zero r20 if CLONE_SETTLS is set. This patch fixes the bug by zeroing regs->r20 only if CLONE_SETTLS is not set. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Matt Turner <mattst88@gmail.com> [bwh: Backported to 3.2: - Remove the settls variable, which was done upstream in commit 25906730ec "alpha: reorganize copy_process(), prepare to saner fork_idle()"] - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>		2018-06-01 00:30:09 +01:00
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boot	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
include/asm	alpha: uapi: Add support for __SANE_USERSPACE_TYPES__	2017-11-11 13:34:35 +00:00
kernel	alpha: fix crash if pthread_create races with signal delivery	2018-06-01 00:30:09 +01:00
lib	Revert "alpha: fix broken network checksum"	2014-04-30 16:23:27 +01:00
math-emu	alpha: change to new Makefile flag variables	2011-01-17 05:42:13 +01:00
mm	vm: add VM_FAULT_SIGSEGV handling support	2015-02-20 00:49:40 +00:00
oprofile	Fix common misspellings	2011-03-31 11:26:23 -03:00
defconfig	defconfig reduction	2010-08-14 22:26:53 +02:00
Kconfig	Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild	2011-11-06 18:54:53 -08:00
Kconfig.debug	alpha/parisc: remove config variable DEBUG_RWLOCK	2008-02-06 10:41:03 -08:00
Makefile	alpha: makefile: don't enforce small data model for kernel builds	2013-09-10 01:57:31 +01:00