Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull second pile of signal handling patches from Al Viro:
 "This one is just task_work_add() series + remaining prereqs for it.

  There probably will be another pull request from that tree this
  cycle - at least for helpers, to get them out of the way for per-arch
  fixes remaining in the tree."

Fix trivial conflict in kernel/irq/manage.c: the merge of Andrew's pile
had brought in commit 97fd75b7b8e0 ("kernel/irq/manage.c: use the
pr_foo() infrastructure to prefix printks") which changed one of the
pr_err() calls that this merge moves around.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  keys: kill task_struct->replacement_session_keyring
  keys: kill the dummy key_replace_session_keyring()
  keys: change keyctl_session_to_parent() to use task_work_add()
  genirq: reimplement exit_irq_thread() hook via task_work_add()
  task_work_add: generic process-context callbacks
  avr32: missed _TIF_NOTIFY_RESUME on one of do_notify_resume callers
  parisc: need to check NOTIFY_RESUME when exiting from syscall
  move key_repace_session_keyring() into tracehook_notify_resume()
  TIF_NOTIFY_RESUME is defined on all targets now

45 files changed, 220 insertions, 186 deletions

diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index 10ab2d74ecbb..f6db3032ddf0 100644
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -590,7 +590,5 @@ do_notify_resume(struct pt_regs *regs, struct switch_stack *sw,
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 17fc36c41cff..63f327dd5198 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -679,7 +679,5 @@ do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
         if (thread_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/avr32/kernel/entry-avr32b.S b/arch/avr32/kernel/entry-avr32b.S
index 169268c40ae2..5e6beb2597a8 100644
--- a/arch/avr32/kernel/entry-avr32b.S
+++ b/arch/avr32/kernel/entry-avr32b.S
@@ -587,7 +587,7 @@ fault_exit_work:
         ld.w    r1, r0[TI_flags]
         rjmp    fault_exit_work
 
-1:      mov     r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK
+1:      mov     r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK | _TIF_NOTIFY_RESUME
         tst     r1, r2
         breq    2f
         unmask_interrupts
diff --git a/arch/avr32/kernel/signal.c b/arch/avr32/kernel/signal.c
index ae386c304bee..e7595ef74f51 100644
--- a/arch/avr32/kernel/signal.c
+++ b/arch/avr32/kernel/signal.c
@@ -321,7 +321,5 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti)
         if (ti->flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/blackfin/kernel/signal.c b/arch/blackfin/kernel/signal.c
index e5bbc1a5edc2..fc9ecce8b6ce 100644
--- a/arch/blackfin/kernel/signal.c
+++ b/arch/blackfin/kernel/signal.c
@@ -336,8 +336,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs)
         if (test_thread_flag(TIF_NOTIFY_RESUME)) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
 
diff --git a/arch/c6x/kernel/signal.c b/arch/c6x/kernel/signal.c
index cf37478c1169..9493f0bbf0a6 100644
--- a/arch/c6x/kernel/signal.c
+++ b/arch/c6x/kernel/signal.c
@@ -364,7 +364,5 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
         if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/cris/kernel/ptrace.c b/arch/cris/kernel/ptrace.c
index d114ad3da9b1..58d44ee1a71f 100644
--- a/arch/cris/kernel/ptrace.c
+++ b/arch/cris/kernel/ptrace.c
@@ -40,7 +40,5 @@ void do_notify_resume(int canrestart, struct pt_regs *regs,
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c
index 8cf5dca01758..595bf1e5a5dc 100644
--- a/arch/frv/kernel/signal.c
+++ b/arch/frv/kernel/signal.c
@@ -562,8 +562,6 @@ asmlinkage void do_notify_resume(__u32 thread_info_flags)
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(__frame);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 
 } /* end do_notify_resume() */
diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c
index d4b0555d2904..e58992ad789e 100644
--- a/arch/h8300/kernel/signal.c
+++ b/arch/h8300/kernel/signal.c
@@ -513,7 +513,5 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/hexagon/kernel/signal.c b/arch/hexagon/kernel/signal.c
index 434866eb0f1c..21a3018cb9bf 100644
--- a/arch/hexagon/kernel/signal.c
+++ b/arch/hexagon/kernel/signal.c
@@ -273,8 +273,6 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
 
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 5e0e86ddb12f..dd6fc1449741 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -199,8 +199,6 @@ do_notify_resume_user(sigset_t *unused, struct sigscratch *scr, long in_syscall)
         if (test_thread_flag(TIF_NOTIFY_RESUME)) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(&scr->pt);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 
         /* copy user rbs to kernel rbs */
diff --git a/arch/m32r/kernel/signal.c b/arch/m32r/kernel/signal.c
index f54d96993ea1..64804f1f5141 100644
--- a/arch/m32r/kernel/signal.c
+++ b/arch/m32r/kernel/signal.c
@@ -383,8 +383,6 @@ void do_notify_resume(struct pt_regs *regs, __u32 thread_info_flags)
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 
         clear_thread_flag(TIF_IRET);
diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
index d9f3d1900eed..973eec60cad4 100644
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -1193,9 +1193,6 @@ void do_notify_resume(struct pt_regs *regs)
         if (test_thread_flag(TIF_SIGPENDING))
                 do_signal(regs);
 
-        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
-        }
 }
diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
index 7f4c7bef1642..5d796e32786e 100644
--- a/arch/microblaze/kernel/signal.c
+++ b/arch/microblaze/kernel/signal.c
@@ -401,9 +401,6 @@ void do_notify_resume(struct pt_regs *regs, int in_syscall)
         if (test_thread_flag(TIF_SIGPENDING))
                 do_signal(regs, in_syscall);
 
-        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
-        }
 }
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index 17f6ee30ad0d..8a6e6d116ab0 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -636,8 +636,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
 
diff --git a/arch/mn10300/kernel/signal.c b/arch/mn10300/kernel/signal.c
index 890cf91767cc..b8b6aa1a6837 100644
--- a/arch/mn10300/kernel/signal.c
+++ b/arch/mn10300/kernel/signal.c
@@ -554,7 +554,5 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(current_frame());
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/openrisc/kernel/signal.c b/arch/openrisc/kernel/signal.c
index e970743251ae..9ae611522953 100644
--- a/arch/openrisc/kernel/signal.c
+++ b/arch/openrisc/kernel/signal.c
@@ -376,7 +376,5 @@ asmlinkage void do_notify_resume(struct pt_regs *regs)
         if (current_thread_info()->flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 07ef351edd57..c7fbc96472f3 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -2032,7 +2032,7 @@ syscall_check_resched:
         .import do_signal,code
 syscall_check_sig:
         LDREG   TI_FLAGS-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r19
-        ldi     (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK), %r26
+        ldi     (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK|_TIF_NOTIFY_RESUME), %r26
         and,COND(<>)    %r19, %r26, %r0
         b,n     syscall_restore /* skip past if we've nothing to do */
 
diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c
index 4b9cb0d546d1..e7a7cd3e1120 100644
--- a/arch/parisc/kernel/signal.c
+++ b/arch/parisc/kernel/signal.c
@@ -638,7 +638,5 @@ void do_notify_resume(struct pt_regs *regs, long in_syscall)
         if (test_thread_flag(TIF_NOTIFY_RESUME)) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index 651c5963662b..bfc3ec1382fb 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -193,8 +193,6 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
 
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index f626232e216c..42a6e8b47f06 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -494,6 +494,4 @@ void do_notify_resume(struct pt_regs *regs)
 {
         clear_thread_flag(TIF_NOTIFY_RESUME);
         tracehook_notify_resume(regs);
-        if (current->replacement_session_keyring)
-                key_replace_session_keyring();
 }
diff --git a/arch/score/kernel/signal.c b/arch/score/kernel/signal.c
index d4a49011c48a..302838d3acf6 100644
--- a/arch/score/kernel/signal.c
+++ b/arch/score/kernel/signal.c
@@ -356,7 +356,5 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
index cb4172c8af7d..9d7bfd66f189 100644
--- a/arch/sh/kernel/signal_32.c
+++ b/arch/sh/kernel/signal_32.c
@@ -626,7 +626,5 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/sh/kernel/signal_64.c b/arch/sh/kernel/signal_64.c
index b589a354c069..aa6428430842 100644
--- a/arch/sh/kernel/signal_64.c
+++ b/arch/sh/kernel/signal_64.c
@@ -685,7 +685,5 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned long thread_info
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
diff --git a/arch/sparc/kernel/signal_32.c b/arch/sparc/kernel/signal_32.c
index 2b7e849f7c65..6b42e8622d12 100644
--- a/arch/sparc/kernel/signal_32.c
+++ b/arch/sparc/kernel/signal_32.c
@@ -590,8 +590,6 @@ void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0,
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
 
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c
index eafaab486b2d..c82cf1cc3965 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -607,8 +607,6 @@ void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
 
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index ba1023d8a021..6be799150501 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -565,8 +565,6 @@ int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
                 return 1;
         }
         if (thread_info_flags & _TIF_SINGLESTEP) {
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 3a2235e0abc3..ccb9a9d283f1 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -117,11 +117,8 @@ void interrupt_end(void)
                 schedule();
         if (test_thread_flag(TIF_SIGPENDING))
                 do_signal();
-        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
                 tracehook_notify_resume(&current->thread.regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
-        }
 }
 
 void exit_thread(void)
diff --git a/arch/unicore32/kernel/signal.c b/arch/unicore32/kernel/signal.c
index 7754df6ef7d4..28782ad47b93 100644
--- a/arch/unicore32/kernel/signal.c
+++ b/arch/unicore32/kernel/signal.c
@@ -464,8 +464,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
         if (thread_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
 }
 
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 965dfda0fd5e..2e937a5ad531 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -827,8 +827,6 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
         }
         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
                 fire_user_return_notifiers();
diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c
index c5e4ec0598d2..ea7e17778a75 100644
--- a/arch/xtensa/kernel/signal.c
+++ b/arch/xtensa/kernel/signal.c
@@ -548,9 +548,6 @@ void do_notify_resume(struct pt_regs *regs)
         if (test_thread_flag(TIF_SIGPENDING))
                 do_signal(regs);
 
-        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
                 tracehook_notify_resume(regs);
-                if (current->replacement_session_keyring)
-                        key_replace_session_keyring();
-        }
 }
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index c91171599cb6..e68a8e53bb59 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -142,8 +142,6 @@ request_any_context_irq(unsigned int irq, irq_handler_t handler,
 extern int __must_check
 request_percpu_irq(unsigned int irq, irq_handler_t handler,
                    const char *devname, void __percpu *percpu_dev_id);
-
-extern void exit_irq_thread(void);
 #else
 
 extern int __must_check
@@ -177,8 +175,6 @@ request_percpu_irq(unsigned int irq, irq_handler_t handler,
 {
         return request_irq(irq, handler, 0, devname, percpu_dev_id);
 }
-
-static inline void exit_irq_thread(void) { }
 #endif
 
 extern void free_irq(unsigned int, void *);
diff --git a/include/linux/key.h b/include/linux/key.h
index 5231800770e1..4cd22ed627ef 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -308,9 +308,6 @@ static inline bool key_is_instantiated(const struct key *key)
 #ifdef CONFIG_SYSCTL
 extern ctl_table key_sysctls[];
 #endif
-
-extern void key_replace_session_keyring(void);
-
 /*
  * the userspace interface
  */
@@ -334,7 +331,6 @@ extern void key_init(void);
 #define key_fsuid_changed(t)            do { } while(0)
 #define key_fsgid_changed(t)            do { } while(0)
 #define key_init()                      do { } while(0)
-#define key_replace_session_keyring()   do { } while(0)
 
 #endif /* CONFIG_KEYS */
 #endif /* __KERNEL__ */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index f45c0b280b5d..660c8ae93471 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1301,11 +1301,6 @@ struct task_struct {
         unsigned sched_reset_on_fork:1;
         unsigned sched_contributes_to_load:1;
 
-#ifdef CONFIG_GENERIC_HARDIRQS
-        /* IRQ handler threads */
-        unsigned irq_thread:1;
-#endif
-
         pid_t pid;
         pid_t tgid;
 
@@ -1313,10 +1308,9 @@ struct task_struct {
         /* Canary value for the -fstack-protector gcc feature */
         unsigned long stack_canary;
 #endif
-
-        /* 
+        /*
          * pointers to (original) parent process, youngest child, younger sibling,
-         * older sibling, respectively.  (p->father can be replaced with 
+         * older sibling, respectively.  (p->father can be replaced with
          * p->real_parent->pid)
          */
         struct task_struct __rcu *real_parent; /* real parent process */
@@ -1363,8 +1357,6 @@ struct task_struct {
                                          * credentials (COW) */
         const struct cred __rcu *cred;  /* effective (overridable) subjective task
                                          * credentials (COW) */
-        struct cred *replacement_session_keyring; /* for KEYCTL_SESSION_TO_PARENT */
-
         char comm[TASK_COMM_LEN]; /* executable name excluding path
                                      - access with [gs]et_task_comm (which lock
                                        it with task_lock())
@@ -1400,6 +1392,8 @@ struct task_struct {
         int (*notifier)(void *priv);
         void *notifier_data;
         sigset_t *notifier_mask;
+        struct hlist_head task_works;
+
         struct audit_context *audit_context;
 #ifdef CONFIG_AUDITSYSCALL
         uid_t loginuid;
diff --git a/include/linux/task_work.h b/include/linux/task_work.h
new file mode 100644
index 000000000000..294d5d5e90b1
--- /dev/null
+++ b/include/linux/task_work.h
@@ -0,0 +1,33 @@
+#ifndef _LINUX_TASK_WORK_H
+#define _LINUX_TASK_WORK_H
+
+#include <linux/list.h>
+#include <linux/sched.h>
+
+struct task_work;
+typedef void (*task_work_func_t)(struct task_work *);
+
+struct task_work {
+        struct hlist_node hlist;
+        task_work_func_t func;
+        void *data;
+};
+
+static inline void
+init_task_work(struct task_work *twork, task_work_func_t func, void *data)
+{
+        twork->func = func;
+        twork->data = data;
+}
+
+int task_work_add(struct task_struct *task, struct task_work *twork, bool);
+struct task_work *task_work_cancel(struct task_struct *, task_work_func_t);
+void task_work_run(void);
+
+static inline void exit_task_work(struct task_struct *task)
+{
+        if (unlikely(!hlist_empty(&task->task_works)))
+                task_work_run();
+}
+
+#endif  /* _LINUX_TASK_WORK_H */
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 51bd91d911c3..6a4d82bedb03 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -49,6 +49,7 @@
 #include <linux/sched.h>
 #include <linux/ptrace.h>
 #include <linux/security.h>
+#include <linux/task_work.h>
 struct linux_binprm;
 
 /*
@@ -153,7 +154,6 @@ static inline void tracehook_signal_handler(int sig, siginfo_t *info,
                 ptrace_notify(SIGTRAP);
 }
 
-#ifdef TIF_NOTIFY_RESUME
 /**
  * set_notify_resume - cause tracehook_notify_resume() to be called
  * @task:               task that will call tracehook_notify_resume()
@@ -165,8 +165,10 @@ static inline void tracehook_signal_handler(int sig, siginfo_t *info,
  */
 static inline void set_notify_resume(struct task_struct *task)
 {
+#ifdef TIF_NOTIFY_RESUME
         if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME))
                 kick_process(task);
+#endif
 }
 
 /**
@@ -184,7 +186,14 @@ static inline void set_notify_resume(struct task_struct *task)
  */
 static inline void tracehook_notify_resume(struct pt_regs *regs)
 {
+        /*
+         * The caller just cleared TIF_NOTIFY_RESUME. This barrier
+         * pairs with task_work_add()->set_notify_resume() after
+         * hlist_add_head(task->task_works);
+         */
+        smp_mb__after_clear_bit();
+        if (unlikely(!hlist_empty(&current->task_works)))
+                task_work_run();
 }
-#endif  /* TIF_NOTIFY_RESUME */
 
 #endif  /* <linux/tracehook.h> */
diff --git a/kernel/Makefile b/kernel/Makefile
index 80be6ca0cc75..6f3d0ae044b2 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -5,7 +5,7 @@
 obj-y     = fork.o exec_domain.o panic.o printk.o \
             cpu.o exit.o itimer.o time.o softirq.o resource.o \
             sysctl.o sysctl_binary.o capability.o ptrace.o timer.o user.o \
-            signal.o sys.o kmod.o workqueue.o pid.o \
+            signal.o sys.o kmod.o workqueue.o pid.o task_work.o \
             rcupdate.o extable.o params.o posix-timers.o \
             kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
             hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
diff --git a/kernel/cred.c b/kernel/cred.c
index 430557ea488f..de728ac50d82 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -207,13 +207,6 @@ void exit_creds(struct task_struct *tsk)
         validate_creds(cred);
         alter_cred_subscribers(cred, -1);
         put_cred(cred);
-
-        cred = (struct cred *) tsk->replacement_session_keyring;
-        if (cred) {
-                tsk->replacement_session_keyring = NULL;
-                validate_creds(cred);
-                put_cred(cred);
-        }
 }
 
 /**
@@ -396,8 +389,6 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
         struct cred *new;
         int ret;
 
-        p->replacement_session_keyring = NULL;
-
         if (
 #ifdef CONFIG_KEYS
                 !p->cred->thread_keyring &&
diff --git a/kernel/exit.c b/kernel/exit.c
index 6d85655353e9..34867cc5b42a 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -946,12 +946,13 @@ void do_exit(long code)
         exit_signals(tsk);  /* sets PF_EXITING */
         /*
          * tsk->flags are checked in the futex code to protect against
-         * an exiting task cleaning up the robust pi futexes.
+         * an exiting task cleaning up the robust pi futexes, and in
+         * task_work_add() to avoid the race with exit_task_work().
          */
         smp_mb();
         raw_spin_unlock_wait(&tsk->pi_lock);
 
-        exit_irq_thread();
+        exit_task_work(tsk);
 
         if (unlikely(in_atomic()))
                 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
diff --git a/kernel/fork.c b/kernel/fork.c
index c55b61ab6d64..ab5211b9e622 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1415,6 +1415,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
          */
         p->group_leader = p;
         INIT_LIST_HEAD(&p->thread_group);
+        INIT_HLIST_HEAD(&p->task_works);
 
         /* Now that the task is set up, run cgroup callbacks if
          * necessary. We need to run them before the task is visible
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 7c475cd3f6e6..ea0c6c2ae6f7 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -16,6 +16,7 @@
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/task_work.h>
 
 #include "internals.h"
 
@@ -775,11 +776,39 @@ static void wake_threads_waitq(struct irq_desc *desc)
                 wake_up(&desc->wait_for_threads);
 }
 
+static void irq_thread_dtor(struct task_work *unused)
+{
+        struct task_struct *tsk = current;
+        struct irq_desc *desc;
+        struct irqaction *action;
+
+        if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
+                return;
+
+        action = kthread_data(tsk);
+
+        pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+               tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
+
+
+        desc = irq_to_desc(action->irq);
+        /*
+         * If IRQTF_RUNTHREAD is set, we need to decrement
+         * desc->threads_active and wake possible waiters.
+         */
+        if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+                wake_threads_waitq(desc);
+
+        /* Prevent a stale desc->threads_oneshot */
+        irq_finalize_oneshot(desc, action);
+}
+
 /*
  * Interrupt handler thread
  */
 static int irq_thread(void *data)
 {
+        struct task_work on_exit_work;
         static const struct sched_param param = {
                 .sched_priority = MAX_USER_RT_PRIO/2,
         };
@@ -795,7 +824,9 @@ static int irq_thread(void *data)
                 handler_fn = irq_thread_fn;
 
         sched_setscheduler(current, SCHED_FIFO, &param);
-        current->irq_thread = 1;
+
+        init_task_work(&on_exit_work, irq_thread_dtor, NULL);
+        task_work_add(current, &on_exit_work, false);
 
         while (!irq_wait_for_interrupt(action)) {
                 irqreturn_t action_ret;
@@ -817,44 +848,11 @@ static int irq_thread(void *data)
          * cannot touch the oneshot mask at this point anymore as
          * __setup_irq() might have given out currents thread_mask
          * again.
-         *
-         * Clear irq_thread. Otherwise exit_irq_thread() would make
-         * fuzz about an active irq thread going into nirvana.
          */
-        current->irq_thread = 0;
+        task_work_cancel(current, irq_thread_dtor);
         return 0;
 }
 
-/*
- * Called from do_exit()
- */
-void exit_irq_thread(void)
-{
-        struct task_struct *tsk = current;
-        struct irq_desc *desc;
-        struct irqaction *action;
-
-        if (!tsk->irq_thread)
-                return;
-
-        action = kthread_data(tsk);
-
-        pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
-               tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
-
-        desc = irq_to_desc(action->irq);
-
-        /*
-         * If IRQTF_RUNTHREAD is set, we need to decrement
-         * desc->threads_active and wake possible waiters.
-         */
-        if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
-                wake_threads_waitq(desc);
-
-        /* Prevent a stale desc->threads_oneshot */
-        irq_finalize_oneshot(desc, action);
-}
-
 static void irq_setup_forced_threading(struct irqaction *new)
 {
         if (!force_irqthreads)
diff --git a/kernel/task_work.c b/kernel/task_work.c
new file mode 100644
index 000000000000..82d1c794066d
--- /dev/null
+++ b/kernel/task_work.c
@@ -0,0 +1,84 @@
+#include <linux/spinlock.h>
+#include <linux/task_work.h>
+#include <linux/tracehook.h>
+
+int
+task_work_add(struct task_struct *task, struct task_work *twork, bool notify)
+{
+        unsigned long flags;
+        int err = -ESRCH;
+
+#ifndef TIF_NOTIFY_RESUME
+        if (notify)
+                return -ENOTSUPP;
+#endif
+        /*
+         * We must not insert the new work if the task has already passed
+         * exit_task_work(). We rely on do_exit()->raw_spin_unlock_wait()
+         * and check PF_EXITING under pi_lock.
+         */
+        raw_spin_lock_irqsave(&task->pi_lock, flags);
+        if (likely(!(task->flags & PF_EXITING))) {
+                hlist_add_head(&twork->hlist, &task->task_works);
+                err = 0;
+        }
+        raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+        /* test_and_set_bit() implies mb(), see tracehook_notify_resume(). */
+        if (likely(!err) && notify)
+                set_notify_resume(task);
+        return err;
+}
+
+struct task_work *
+task_work_cancel(struct task_struct *task, task_work_func_t func)
+{
+        unsigned long flags;
+        struct task_work *twork;
+        struct hlist_node *pos;
+
+        raw_spin_lock_irqsave(&task->pi_lock, flags);
+        hlist_for_each_entry(twork, pos, &task->task_works, hlist) {
+                if (twork->func == func) {
+                        hlist_del(&twork->hlist);
+                        goto found;
+                }
+        }
+        twork = NULL;
+ found:
+        raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+        return twork;
+}
+
+void task_work_run(void)
+{
+        struct task_struct *task = current;
+        struct hlist_head task_works;
+        struct hlist_node *pos;
+
+        raw_spin_lock_irq(&task->pi_lock);
+        hlist_move_list(&task->task_works, &task_works);
+        raw_spin_unlock_irq(&task->pi_lock);
+
+        if (unlikely(hlist_empty(&task_works)))
+                return;
+        /*
+         * We use hlist to save the space in task_struct, but we want fifo.
+         * Find the last entry, the list should be short, then process them
+         * in reverse order.
+         */
+        for (pos = task_works.first; pos->next; pos = pos->next)
+                ;
+
+        for (;;) {
+                struct hlist_node **pprev = pos->pprev;
+                struct task_work *twork = container_of(pos, struct task_work,
+                                                        hlist);
+                twork->func(twork);
+
+                if (pprev == &task_works.first)
+                        break;
+                pos = container_of(pprev, struct hlist_node, next);
+        }
+}
diff --git a/security/keys/internal.h b/security/keys/internal.h
index f711b094ed41..3dcbf86b0d31 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -14,6 +14,7 @@
 
 #include <linux/sched.h>
 #include <linux/key-type.h>
+#include <linux/task_work.h>
 
 #ifdef __KDEBUG
 #define kenter(FMT, ...) \
@@ -148,6 +149,7 @@ extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
 #define KEY_LOOKUP_FOR_UNLINK   0x04
 
 extern long join_session_keyring(const char *name);
+extern void key_change_session_keyring(struct task_work *twork);
 
 extern struct work_struct key_gc_work;
 extern unsigned key_gc_delay;
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 21907ea35b15..0f5b3f027299 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1454,50 +1454,57 @@ long keyctl_get_security(key_serial_t keyid,
  */
 long keyctl_session_to_parent(void)
 {
-#ifdef TIF_NOTIFY_RESUME
         struct task_struct *me, *parent;
         const struct cred *mycred, *pcred;
-        struct cred *cred, *oldcred;
+        struct task_work *newwork, *oldwork;
         key_ref_t keyring_r;
+        struct cred *cred;
         int ret;
 
         keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
         if (IS_ERR(keyring_r))
                 return PTR_ERR(keyring_r);
 
+        ret = -ENOMEM;
+        newwork = kmalloc(sizeof(struct task_work), GFP_KERNEL);
+        if (!newwork)
+                goto error_keyring;
+
         /* our parent is going to need a new cred struct, a new tgcred struct
          * and new security data, so we allocate them here to prevent ENOMEM in
          * our parent */
-        ret = -ENOMEM;
         cred = cred_alloc_blank();
         if (!cred)
-                goto error_keyring;
+                goto error_newwork;
 
         cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
-        keyring_r = NULL;
+        init_task_work(newwork, key_change_session_keyring, cred);
 
         me = current;
         rcu_read_lock();
         write_lock_irq(&tasklist_lock);
 
-        parent = me->real_parent;
         ret = -EPERM;
+        oldwork = NULL;
+        parent = me->real_parent;
 
         /* the parent mustn't be init and mustn't be a kernel thread */
         if (parent->pid <= 1 || !parent->mm)
-                goto not_permitted;
+                goto unlock;
 
         /* the parent must be single threaded */
         if (!thread_group_empty(parent))
-                goto not_permitted;
+                goto unlock;
 
         /* the parent and the child must have different session keyrings or
          * there's no point */
         mycred = current_cred();
         pcred = __task_cred(parent);
         if (mycred == pcred ||
-            mycred->tgcred->session_keyring == pcred->tgcred->session_keyring)
-                goto already_same;
+            mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) {
+                ret = 0;
+                goto unlock;
+        }
 
         /* the parent must have the same effective ownership and mustn't be
          * SUID/SGID */
@@ -1507,50 +1514,40 @@ long keyctl_session_to_parent(void)
             pcred->gid  != mycred->egid ||
             pcred->egid != mycred->egid ||
             pcred->sgid != mycred->egid)
-                goto not_permitted;
+                goto unlock;
 
         /* the keyrings must have the same UID */
         if ((pcred->tgcred->session_keyring &&
              pcred->tgcred->session_keyring->uid != mycred->euid) ||
             mycred->tgcred->session_keyring->uid != mycred->euid)
-                goto not_permitted;
+                goto unlock;
 
-        /* if there's an already pending keyring replacement, then we replace
-         * that */
-        oldcred = parent->replacement_session_keyring;
+        /* cancel an already pending keyring replacement */
+        oldwork = task_work_cancel(parent, key_change_session_keyring);
 
         /* the replacement session keyring is applied just prior to userspace
          * restarting */
-        parent->replacement_session_keyring = cred;
-        cred = NULL;
-        set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME);
-
+        ret = task_work_add(parent, newwork, true);
+        if (!ret)
+                newwork = NULL;
+unlock:
         write_unlock_irq(&tasklist_lock);
         rcu_read_unlock();
-        if (oldcred)
-                put_cred(oldcred);
-        return 0;
-
-already_same:
-        ret = 0;
-not_permitted:
-        write_unlock_irq(&tasklist_lock);
-        rcu_read_unlock();
-        put_cred(cred);
+        if (oldwork) {
+                put_cred(oldwork->data);
+                kfree(oldwork);
+        }
+        if (newwork) {
+                put_cred(newwork->data);
+                kfree(newwork);
+        }
         return ret;
 
+error_newwork:
+        kfree(newwork);
 error_keyring:
         key_ref_put(keyring_r);
         return ret;
-
-#else /* !TIF_NOTIFY_RESUME */
-        /*
-         * To be removed when TIF_NOTIFY_RESUME has been implemented on
-         * m68k/xtensa
-         */
-#warning TIF_NOTIFY_RESUME not implemented
-        return -EOPNOTSUPP;
-#endif /* !TIF_NOTIFY_RESUME */
 }
 
 /*
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index d71056db7b67..4ad54eea1ea4 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -834,23 +834,17 @@ error:
  * Replace a process's session keyring on behalf of one of its children when
  * the target  process is about to resume userspace execution.
  */
-void key_replace_session_keyring(void)
+void key_change_session_keyring(struct task_work *twork)
 {
-        const struct cred *old;
-        struct cred *new;
-
-        if (!current->replacement_session_keyring)
-                return;
+        const struct cred *old = current_cred();
+        struct cred *new = twork->data;
 
-        write_lock_irq(&tasklist_lock);
-        new = current->replacement_session_keyring;
-        current->replacement_session_keyring = NULL;
-        write_unlock_irq(&tasklist_lock);
-
-        if (!new)
+        kfree(twork);
+        if (unlikely(current->flags & PF_EXITING)) {
+                put_cred(new);
                 return;
+        }
 
-        old = current_cred();
         new->  uid      = old->  uid;
         new-> euid      = old-> euid;
         new-> suid      = old-> suid;