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4c03d46991
Many people reported preemption/reschedule problems with i386 kernels
for .13 and .14. After Michele bisected this to a combination of
3e8e42c69bb ("sched: Revert need_resched() to look at TIF_NEED_RESCHED")
ded7975475 ("irq: Force hardirq exit's softirq processing on its own stack")
it finally dawned on me that i386's current_thread_info() was to
blame.
When we are on interrupt/exception stacks, we fail to observe the
right TIF_NEED_RESCHED bit and therefore the PREEMPT_NEED_RESCHED
folding malfunctions.
Current upstream fixes this by making i386 behave the same as x86_64
already did:
2432e1364b ("x86: Nuke the supervisor_stack field in i386 thread_info")
b807902a88 ("x86: Nuke GET_THREAD_INFO_WITH_ESP() macro for i386")
0788aa6a23 ("x86: Prepare removal of previous_esp from i386 thread_info structure")
198d208df4 ("x86: Keep thread_info on thread stack in x86_32")
However, that is far too much to stuff into -stable. Therefore I
propose we merge the below patch which uses task_thread_info(current)
for tif_need_resched() instead of the ESP based current_thread_info().
This makes sure we always observe the one true TIF_NEED_RESCHED bit
and things will work as expected again.
Cc: bp@alien8.de
Cc: fweisbec@gmail.com
Cc: david.a.cohen@linux.intel.com
Cc: mingo@kernel.org
Cc: fweisbec@gmail.com
Cc: greg@kroah.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: gregkh@linuxfoundation.org
Cc: pbonzini@redhat.com
Cc: rostedt@goodmis.org
Cc: stefan.bader@canonical.com
Cc: mingo@kernel.org
Cc: toralf.foerster@gmx.de
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: torvalds@linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: <stable@vger.kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: <stable-commits@vger.kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: peterz@infradead.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: barra_cuda@katamail.com
Tested-by: Stefan Bader <stefan.bader@canonical.com>
Tested-by: Toralf F¿rster <toralf.foerster@gmx.de>
Tested-by: Michele Ballabio <barra_cuda@katamail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140409142447.GD13658@twins.programming.kicks-ass.net
165 lines
4.3 KiB
C
165 lines
4.3 KiB
C
/* thread_info.h: common low-level thread information accessors
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*
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* Copyright (C) 2002 David Howells (dhowells@redhat.com)
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* - Incorporating suggestions made by Linus Torvalds
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*/
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#ifndef _LINUX_THREAD_INFO_H
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#define _LINUX_THREAD_INFO_H
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#include <linux/types.h>
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#include <linux/bug.h>
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struct timespec;
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struct compat_timespec;
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/*
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* System call restart block.
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*/
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struct restart_block {
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long (*fn)(struct restart_block *);
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union {
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/* For futex_wait and futex_wait_requeue_pi */
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struct {
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u32 __user *uaddr;
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u32 val;
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u32 flags;
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u32 bitset;
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u64 time;
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u32 __user *uaddr2;
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} futex;
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/* For nanosleep */
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struct {
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clockid_t clockid;
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struct timespec __user *rmtp;
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#ifdef CONFIG_COMPAT
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struct compat_timespec __user *compat_rmtp;
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#endif
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u64 expires;
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} nanosleep;
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/* For poll */
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struct {
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struct pollfd __user *ufds;
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int nfds;
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int has_timeout;
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unsigned long tv_sec;
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unsigned long tv_nsec;
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} poll;
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};
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};
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extern long do_no_restart_syscall(struct restart_block *parm);
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#include <linux/bitops.h>
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#include <asm/thread_info.h>
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#ifdef __KERNEL__
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#ifdef CONFIG_DEBUG_STACK_USAGE
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# define THREADINFO_GFP (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
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#else
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# define THREADINFO_GFP (GFP_KERNEL | __GFP_NOTRACK)
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#endif
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#define THREADINFO_GFP_ACCOUNTED (THREADINFO_GFP | __GFP_KMEMCG)
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/*
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* flag set/clear/test wrappers
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* - pass TIF_xxxx constants to these functions
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*/
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static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
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{
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set_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
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{
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clear_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_and_set_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_bit(flag, (unsigned long *)&ti->flags);
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}
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#define set_thread_flag(flag) \
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set_ti_thread_flag(current_thread_info(), flag)
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#define clear_thread_flag(flag) \
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clear_ti_thread_flag(current_thread_info(), flag)
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#define test_and_set_thread_flag(flag) \
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test_and_set_ti_thread_flag(current_thread_info(), flag)
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#define test_and_clear_thread_flag(flag) \
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test_and_clear_ti_thread_flag(current_thread_info(), flag)
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#define test_thread_flag(flag) \
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test_ti_thread_flag(current_thread_info(), flag)
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static inline __deprecated void set_need_resched(void)
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{
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/*
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* Use of this function in deprecated.
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*
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* As of this writing there are only a few users in the DRM tree left
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* all of which are wrong and can be removed without causing too much
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* grief.
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*
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* The DRM people are aware and are working on removing the last few
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* instances.
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*/
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}
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#if defined TIF_RESTORE_SIGMASK && !defined HAVE_SET_RESTORE_SIGMASK
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/*
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* An arch can define its own version of set_restore_sigmask() to get the
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* job done however works, with or without TIF_RESTORE_SIGMASK.
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*/
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#define HAVE_SET_RESTORE_SIGMASK 1
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/**
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* set_restore_sigmask() - make sure saved_sigmask processing gets done
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*
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* This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
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* will run before returning to user mode, to process the flag. For
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* all callers, TIF_SIGPENDING is already set or it's no harm to set
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* it. TIF_RESTORE_SIGMASK need not be in the set of bits that the
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* arch code will notice on return to user mode, in case those bits
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* are scarce. We set TIF_SIGPENDING here to ensure that the arch
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* signal code always gets run when TIF_RESTORE_SIGMASK is set.
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*/
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static inline void set_restore_sigmask(void)
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{
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set_thread_flag(TIF_RESTORE_SIGMASK);
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WARN_ON(!test_thread_flag(TIF_SIGPENDING));
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}
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static inline void clear_restore_sigmask(void)
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{
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clear_thread_flag(TIF_RESTORE_SIGMASK);
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}
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static inline bool test_restore_sigmask(void)
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{
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return test_thread_flag(TIF_RESTORE_SIGMASK);
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}
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static inline bool test_and_clear_restore_sigmask(void)
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{
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return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
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}
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#endif /* TIF_RESTORE_SIGMASK && !HAVE_SET_RESTORE_SIGMASK */
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#ifndef HAVE_SET_RESTORE_SIGMASK
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#error "no set_restore_sigmask() provided and default one won't work"
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#endif
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#endif /* __KERNEL__ */
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#endif /* _LINUX_THREAD_INFO_H */
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