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Mikulas Patocka 0b2e4fd226 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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>		History 2018-06-16 22:21:56 +01:00
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boot	alpha: boot: fix build breakage introduced by system.h disintegration	2013-03-08 15:05:34 -08:00
include	alpha: uapi: Add support for __SANE_USERSPACE_TYPES__	2017-11-11 13:33:33 +00:00
kernel	alpha: fix crash if pthread_create races with signal delivery	2018-06-16 22:21:56 +01:00
lib	alpha: fix broken network checksum	2014-01-31 09:21:55 -08:00
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	2015-02-04 10:58:27 +00:00
oprofile	oprofilefs_create_...() do not need superblock argument	2013-09-03 22:52:48 -04:00
defconfig	defconfig reduction	2010-08-14 22:26:53 +02:00
Kconfig	Merge git://git.infradead.org/users/eparis/audit	2014-04-12 12:38:53 -07:00
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	2013-04-07 12:59:30 -07:00