[PATCH v3 6/6] freezer,sched: Rewrite core freezer logic

Peter Zijlstra
2021-10-09T10:20:20Z

This here rewrites the core freezer to behave better wrt thawing. By
replacing PF_FROZEN with TASK_FROZEN, a special block state, it is
ensured frozen tasks stay frozen until thawed and don't randomly wake
up early, as is currently possible.

As such, it does away with PF_FROZEN and PF_FREEZER_SKIP, freeing up
two PF_flags (yay).

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
drivers/android/binder.c | 4
drivers/media/pci/pt3/pt3.c | 4
fs/cifs/inode.c | 4
fs/cifs/transport.c | 5
fs/coredump.c | 5
fs/nfs/file.c | 3
fs/nfs/inode.c | 12 --
fs/nfs/nfs3proc.c | 3
fs/nfs/nfs4proc.c | 14 +-
fs/nfs/nfs4state.c | 3
fs/nfs/pnfs.c | 4
fs/xfs/xfs_trans_ail.c | 8 -
include/linux/completion.h | 1
include/linux/freezer.h | 244 +----------------------------------------
include/linux/sched.h | 41 +++---
include/linux/sunrpc/sched.h | 7 -
include/linux/wait.h | 40 +++++-
kernel/cgroup/legacy_freezer.c | 23 +--
kernel/exit.c | 4
kernel/fork.c | 5
kernel/freezer.c | 132 +++++++++++++++-------
kernel/futex.c | 4
kernel/hung_task.c | 4
kernel/power/main.c | 6 -
kernel/power/process.c | 10 -
kernel/ptrace.c | 2
kernel/sched/completion.c | 9 +
kernel/sched/core.c | 19 ++-
kernel/signal.c | 14 +-
kernel/time/hrtimer.c | 4
kernel/umh.c | 20 +--
mm/khugepaged.c | 4
net/sunrpc/sched.c | 12 --
net/unix/af_unix.c | 8 -
34 files changed, 274 insertions(+), 408 deletions(-)

--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3722,10 +3722,9 @@ static int binder_wait_for_work(struct b
struct binder_proc *proc = thread->proc;
int ret = 0;

- freezer_do_not_count();
binder_inner_proc_lock(proc);
for (;;) {
- prepare_to_wait(&thread->wait, &wait, TASK_INTERRUPTIBLE);
+ prepare_to_wait(&thread->wait, &wait, TASK_INTERRUPTIBLE|TASK_FREEZABLE);
if (binder_has_work_ilocked(thread, do_proc_work))
break;
if (do_proc_work)
@@ -3742,7 +3741,6 @@ static int binder_wait_for_work(struct b
}
finish_wait(&thread->wait, &wait);
binder_inner_proc_unlock(proc);
- freezer_count();

return ret;
}
--- a/drivers/media/pci/pt3/pt3.c
+++ b/drivers/media/pci/pt3/pt3.c
@@ -445,8 +445,8 @@ static int pt3_fetch_thread(void *data)
pt3_proc_dma(adap);

delay = ktime_set(0, PT3_FETCH_DELAY * NSEC_PER_MSEC);
- set_current_state(TASK_UNINTERRUPTIBLE);
- freezable_schedule_hrtimeout_range(&delay,
+ set_current_state(TASK_UNINTERRUPTIBLE|TASK_FREEZABLE);
+ schedule_hrtimeout_range(&delay,
PT3_FETCH_DELAY_DELTA * NSEC_PER_MSEC,
HRTIMER_MODE_REL);
}
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -2285,7 +2285,7 @@ cifs_invalidate_mapping(struct inode *in
static int
cifs_wait_bit_killable(struct wait_bit_key *key, int mode)
{
- freezable_schedule_unsafe();
+ schedule();
if (signal_pending_state(mode, current))
return -ERESTARTSYS;
return 0;
@@ -2303,7 +2303,7 @@ cifs_revalidate_mapping(struct inode *in
return 0;

rc = wait_on_bit_lock_action(flags, CIFS_INO_LOCK, cifs_wait_bit_killable,
- TASK_KILLABLE);
+ TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
if (rc)
return rc;

--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -760,8 +760,9 @@ wait_for_response(struct TCP_Server_Info
{
int error;

- error = wait_event_freezekillable_unsafe(server->response_q,
- midQ->mid_state != MID_REQUEST_SUBMITTED);
+ error = wait_event_state(server->response_q,
+ midQ->mid_state != MID_REQUEST_SUBMITTED,
+ (TASK_KILLABLE|TASK_FREEZABLE_UNSAFE));
if (error < 0)
return -ERESTARTSYS;

--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -465,9 +465,8 @@ static int coredump_wait(int exit_code,
if (core_waiters > 0) {
struct core_thread *ptr;

- freezer_do_not_count();
- wait_for_completion(&core_state->startup);
- freezer_count();
+ wait_for_completion_state(&core_state->startup,
+ TASK_UNINTERRUPTIBLE|TASK_FREEZABLE);
/*
* Wait for all the threads to become inactive, so that
* all the thread context (extended register state, like
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -558,7 +558,8 @@ static vm_fault_t nfs_vm_page_mkwrite(st
nfs_fscache_wait_on_page_write(NFS_I(inode), page);

wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
- nfs_wait_bit_killable, TASK_KILLABLE);
+ nfs_wait_bit_killable,
+ TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);

lock_page(page);
mapping = page_file_mapping(page);
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -72,18 +72,13 @@ nfs_fattr_to_ino_t(struct nfs_fattr *fat
return nfs_fileid_to_ino_t(fattr->fileid);
}

-static int nfs_wait_killable(int mode)
+int nfs_wait_bit_killable(struct wait_bit_key *key, int mode)
{
- freezable_schedule_unsafe();
+ schedule();
if (signal_pending_state(mode, current))
return -ERESTARTSYS;
return 0;
}
-
-int nfs_wait_bit_killable(struct wait_bit_key *key, int mode)
-{
- return nfs_wait_killable(mode);
-}
EXPORT_SYMBOL_GPL(nfs_wait_bit_killable);

/**
@@ -1327,7 +1322,8 @@ int nfs_clear_invalid_mapping(struct add
*/
for (;;) {
ret = wait_on_bit_action(bitlock, NFS_INO_INVALIDATING,
- nfs_wait_bit_killable, TASK_KILLABLE);
+ nfs_wait_bit_killable,
+ TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
if (ret)
goto out;
spin_lock(&inode->i_lock);
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -36,7 +36,8 @@ nfs3_rpc_wrapper(struct rpc_clnt *clnt,
res = rpc_call_sync(clnt, msg, flags);
if (res != -EJUKEBOX)
break;
- freezable_schedule_timeout_killable_unsafe(NFS_JUKEBOX_RETRY_TIME);
+ __set_current_state(TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
+ schedule_timeout(NFS_JUKEBOX_RETRY_TIME);
res = -ERESTARTSYS;
} while (!fatal_signal_pending(current));
return res;
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -411,8 +411,8 @@ static int nfs4_delay_killable(long *tim
{
might_sleep();

- freezable_schedule_timeout_killable_unsafe(
- nfs4_update_delay(timeout));
+ __set_current_state(TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
+ schedule_timeout(nfs4_update_delay(timeout));
if (!__fatal_signal_pending(current))
return 0;
return -EINTR;
@@ -422,7 +422,8 @@ static int nfs4_delay_interruptible(long
{
might_sleep();

- freezable_schedule_timeout_interruptible_unsafe(nfs4_update_delay(timeout));
+ __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE_UNSAFE);
+ schedule_timeout(nfs4_update_delay(timeout));
if (!signal_pending(current))
return 0;
return __fatal_signal_pending(current) ? -EINTR :-ERESTARTSYS;
@@ -7320,7 +7321,8 @@ nfs4_retry_setlk_simple(struct nfs4_stat
status = nfs4_proc_setlk(state, cmd, request);
if ((status != -EAGAIN) || IS_SETLK(cmd))
break;
- freezable_schedule_timeout_interruptible(timeout);
+ __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+ schedule_timeout(timeout);
timeout *= 2;
timeout = min_t(unsigned long, NFS4_LOCK_MAXTIMEOUT, timeout);
status = -ERESTARTSYS;
@@ -7388,10 +7390,8 @@ nfs4_retry_setlk(struct nfs4_state *stat
break;

status = -ERESTARTSYS;
- freezer_do_not_count();
- wait_woken(&waiter.wait, TASK_INTERRUPTIBLE,
+ wait_woken(&waiter.wait, TASK_INTERRUPTIBLE|TASK_FREEZABLE,
NFS4_LOCK_MAXTIMEOUT);
- freezer_count();
} while (!signalled());

remove_wait_queue(q, &waiter.wait);
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1307,7 +1307,8 @@ int nfs4_wait_clnt_recover(struct nfs_cl

refcount_inc(&clp->cl_count);
res = wait_on_bit_action(&clp->cl_state, NFS4CLNT_MANAGER_RUNNING,
- nfs_wait_bit_killable, TASK_KILLABLE);
+ nfs_wait_bit_killable,
+ TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
if (res)
goto out;
if (clp->cl_cons_state < 0)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1896,7 +1896,7 @@ static int pnfs_prepare_to_retry_layoutg
pnfs_layoutcommit_inode(lo->plh_inode, false);
return wait_on_bit_action(&lo->plh_flags, NFS_LAYOUT_RETURN,
nfs_wait_bit_killable,
- TASK_KILLABLE);
+ TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
}

static void nfs_layoutget_begin(struct pnfs_layout_hdr *lo)
@@ -3176,7 +3176,7 @@ pnfs_layoutcommit_inode(struct inode *in
status = wait_on_bit_lock_action(&nfsi->flags,
NFS_INO_LAYOUTCOMMITTING,
nfs_wait_bit_killable,
- TASK_KILLABLE);
+ TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
if (status)
goto out;
}
--- a/fs/xfs/xfs_trans_ail.c
+++ b/fs/xfs/xfs_trans_ail.c
@@ -590,9 +590,9 @@ xfsaild(

while (1) {
if (tout && tout <= 20)
- set_current_state(TASK_KILLABLE);
+ set_current_state(TASK_KILLABLE|TASK_FREEZABLE);
else
- set_current_state(TASK_INTERRUPTIBLE);
+ set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);

/*
* Check kthread_should_stop() after we set the task state to
@@ -641,14 +641,14 @@ xfsaild(
ailp->ail_target == ailp->ail_target_prev &&
list_empty(&ailp->ail_buf_list)) {
spin_unlock(&ailp->ail_lock);
- freezable_schedule();
+ schedule();
tout = 0;
continue;
}
spin_unlock(&ailp->ail_lock);

if (tout)
- freezable_schedule_timeout(msecs_to_jiffies(tout));
+ schedule_timeout(msecs_to_jiffies(tout));

__set_current_state(TASK_RUNNING);

--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -103,6 +103,7 @@ extern void wait_for_completion(struct c
extern void wait_for_completion_io(struct completion *);
extern int wait_for_completion_interruptible(struct completion *x);
extern int wait_for_completion_killable(struct completion *x);
+extern int wait_for_completion_state(struct completion *x, unsigned int state);
extern unsigned long wait_for_completion_timeout(struct completion *x,
unsigned long timeout);
extern unsigned long wait_for_completion_io_timeout(struct completion *x,
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -8,9 +8,11 @@
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/atomic.h>
+#include <linux/jump_label.h>

#ifdef CONFIG_FREEZER
-extern atomic_t system_freezing_cnt; /* nr of freezing conds in effect */
+DECLARE_STATIC_KEY_FALSE(freezer_active);
+
extern bool pm_freezing; /* PM freezing in effect */
extern bool pm_nosig_freezing; /* PM nosig freezing in effect */

@@ -22,10 +24,7 @@ extern unsigned int freeze_timeout_msecs
/*
* Check if a process has been frozen
*/
-static inline bool frozen(struct task_struct *p)
-{
- return p->flags & PF_FROZEN;
-}
+extern bool frozen(struct task_struct *p);

extern bool freezing_slow_path(struct task_struct *p);

@@ -34,9 +33,10 @@ extern bool freezing_slow_path(struct ta
*/
static inline bool freezing(struct task_struct *p)
{
- if (likely(!atomic_read(&system_freezing_cnt)))
- return false;
- return freezing_slow_path(p);
+ if (static_branch_unlikely(&freezer_active))
+ return freezing_slow_path(p);
+
+ return false;
}

/* Takes and releases task alloc lock using task_lock() */
@@ -48,23 +48,14 @@ extern int freeze_kernel_threads(void);
extern void thaw_processes(void);
extern void thaw_kernel_threads(void);

-/*
- * DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION
- * If try_to_freeze causes a lockdep warning it means the caller may deadlock
- */
-static inline bool try_to_freeze_unsafe(void)
+static inline bool try_to_freeze(void)
{
might_sleep();
if (likely(!freezing(current)))
return false;
- return __refrigerator(false);
-}
-
-static inline bool try_to_freeze(void)
-{
if (!(current->flags & PF_NOFREEZE))
debug_check_no_locks_held();
- return try_to_freeze_unsafe();
+ return __refrigerator(false);
}

extern bool freeze_task(struct task_struct *p);
@@ -79,195 +70,6 @@ static inline bool cgroup_freezing(struc
}
#endif /* !CONFIG_CGROUP_FREEZER */

-/*
- * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it
- * calls wait_for_completion(&vfork) and reset right after it returns from this
- * function. Next, the parent should call try_to_freeze() to freeze itself
- * appropriately in case the child has exited before the freezing of tasks is
- * complete. However, we don't want kernel threads to be frozen in unexpected
- * places, so we allow them to block freeze_processes() instead or to set
- * PF_NOFREEZE if needed. Fortunately, in the ____call_usermodehelper() case the
- * parent won't really block freeze_processes(), since ____call_usermodehelper()
- * (the child) does a little before exec/exit and it can't be frozen before
- * waking up the parent.
- */
-
-
-/**
- * freezer_do_not_count - tell freezer to ignore %current
- *
- * Tell freezers to ignore the current task when determining whether the
- * target frozen state is reached. IOW, the current task will be
- * considered frozen enough by freezers.
- *
- * The caller shouldn't do anything which isn't allowed for a frozen task
- * until freezer_cont() is called. Usually, freezer[_do_not]_count() pair
- * wrap a scheduling operation and nothing much else.
- */
-static inline void freezer_do_not_count(void)
-{
- current->flags |= PF_FREEZER_SKIP;
-}
-
-/**
- * freezer_count - tell freezer to stop ignoring %current
- *
- * Undo freezer_do_not_count(). It tells freezers that %current should be
- * considered again and tries to freeze if freezing condition is already in
- * effect.
- */
-static inline void freezer_count(void)
-{
- current->flags &= ~PF_FREEZER_SKIP;
- /*
- * If freezing is in progress, the following paired with smp_mb()
- * in freezer_should_skip() ensures that either we see %true
- * freezing() or freezer_should_skip() sees !PF_FREEZER_SKIP.
- */
- smp_mb();
- try_to_freeze();
-}
-
-/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
-static inline void freezer_count_unsafe(void)
-{
- current->flags &= ~PF_FREEZER_SKIP;
- smp_mb();
- try_to_freeze_unsafe();
-}
-
-/**
- * freezer_should_skip - whether to skip a task when determining frozen
- * state is reached
- * @p: task in quesion
- *
- * This function is used by freezers after establishing %true freezing() to
- * test whether a task should be skipped when determining the target frozen
- * state is reached. IOW, if this function returns %true, @p is considered
- * frozen enough.
- */
-static inline bool freezer_should_skip(struct task_struct *p)
-{
- /*
- * The following smp_mb() paired with the one in freezer_count()
- * ensures that either freezer_count() sees %true freezing() or we
- * see cleared %PF_FREEZER_SKIP and return %false. This makes it
- * impossible for a task to slip frozen state testing after
- * clearing %PF_FREEZER_SKIP.
- */
- smp_mb();
- return p->flags & PF_FREEZER_SKIP;
-}
-
-/*
- * These functions are intended to be used whenever you want allow a sleeping
- * task to be frozen. Note that neither return any clear indication of
- * whether a freeze event happened while in this function.
- */
-
-/* Like schedule(), but should not block the freezer. */
-static inline void freezable_schedule(void)
-{
- freezer_do_not_count();
- schedule();
- freezer_count();
-}
-
-/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
-static inline void freezable_schedule_unsafe(void)
-{
- freezer_do_not_count();
- schedule();
- freezer_count_unsafe();
-}
-
-/*
- * Like schedule_timeout(), but should not block the freezer. Do not
- * call this with locks held.
- */
-static inline long freezable_schedule_timeout(long timeout)
-{
- long __retval;
- freezer_do_not_count();
- __retval = schedule_timeout(timeout);
- freezer_count();
- return __retval;
-}
-
-/*
- * Like schedule_timeout_interruptible(), but should not block the freezer. Do not
- * call this with locks held.
- */
-static inline long freezable_schedule_timeout_interruptible(long timeout)
-{
- long __retval;
- freezer_do_not_count();
- __retval = schedule_timeout_interruptible(timeout);
- freezer_count();
- return __retval;
-}
-
-/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
-static inline long freezable_schedule_timeout_interruptible_unsafe(long timeout)
-{
- long __retval;
-
- freezer_do_not_count();
- __retval = schedule_timeout_interruptible(timeout);
- freezer_count_unsafe();
- return __retval;
-}
-
-/* Like schedule_timeout_killable(), but should not block the freezer. */
-static inline long freezable_schedule_timeout_killable(long timeout)
-{
- long __retval;
- freezer_do_not_count();
- __retval = schedule_timeout_killable(timeout);
- freezer_count();
- return __retval;
-}
-
-/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
-static inline long freezable_schedule_timeout_killable_unsafe(long timeout)
-{
- long __retval;
- freezer_do_not_count();
- __retval = schedule_timeout_killable(timeout);
- freezer_count_unsafe();
- return __retval;
-}
-
-/*
- * Like schedule_hrtimeout_range(), but should not block the freezer. Do not
- * call this with locks held.
- */
-static inline int freezable_schedule_hrtimeout_range(ktime_t *expires,
- u64 delta, const enum hrtimer_mode mode)
-{
- int __retval;
- freezer_do_not_count();
- __retval = schedule_hrtimeout_range(expires, delta, mode);
- freezer_count();
- return __retval;
-}
-
-/*
- * Freezer-friendly wrappers around wait_event_interruptible(),
- * wait_event_killable() and wait_event_interruptible_timeout(), originally
- * defined in <linux/wait.h>
- */
-
-/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
-#define wait_event_freezekillable_unsafe(wq, condition) \
-({ \
- int __retval; \
- freezer_do_not_count(); \
- __retval = wait_event_killable(wq, (condition)); \
- freezer_count_unsafe(); \
- __retval; \
-})
-
#else /* !CONFIG_FREEZER */
static inline bool frozen(struct task_struct *p) { return false; }
static inline bool freezing(struct task_struct *p) { return false; }
@@ -281,35 +83,9 @@ static inline void thaw_kernel_threads(v

static inline bool try_to_freeze(void) { return false; }

-static inline void freezer_do_not_count(void) {}
static inline void freezer_count(void) {}
-static inline int freezer_should_skip(struct task_struct *p) { return 0; }
static inline void set_freezable(void) {}

-#define freezable_schedule() schedule()
-
-#define freezable_schedule_unsafe() schedule()
-
-#define freezable_schedule_timeout(timeout) schedule_timeout(timeout)
-
-#define freezable_schedule_timeout_interruptible(timeout) \
- schedule_timeout_interruptible(timeout)
-
-#define freezable_schedule_timeout_interruptible_unsafe(timeout) \
- schedule_timeout_interruptible(timeout)
-
-#define freezable_schedule_timeout_killable(timeout) \
- schedule_timeout_killable(timeout)
-
-#define freezable_schedule_timeout_killable_unsafe(timeout) \
- schedule_timeout_killable(timeout)
-
-#define freezable_schedule_hrtimeout_range(expires, delta, mode) \
- schedule_hrtimeout_range(expires, delta, mode)
-
-#define wait_event_freezekillable_unsafe(wq, condition) \
- wait_event_killable(wq, condition)
-
#endif /* !CONFIG_FREEZER */

#endif /* FREEZER_H_INCLUDED */
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -80,25 +80,32 @@ struct task_group;
*/

/* Used in tsk->state: */
-#define TASK_RUNNING 0x0000
-#define TASK_INTERRUPTIBLE 0x0001
-#define TASK_UNINTERRUPTIBLE 0x0002
-#define __TASK_STOPPED 0x0004
-#define __TASK_TRACED 0x0008
+#define TASK_RUNNING 0x000000
+#define TASK_INTERRUPTIBLE 0x000001
+#define TASK_UNINTERRUPTIBLE 0x000002
+#define __TASK_STOPPED 0x000004
+#define __TASK_TRACED 0x000008
/* Used in tsk->exit_state: */
-#define EXIT_DEAD 0x0010
-#define EXIT_ZOMBIE 0x0020
+#define EXIT_DEAD 0x000010
+#define EXIT_ZOMBIE 0x000020
#define EXIT_TRACE (EXIT_ZOMBIE | EXIT_DEAD)
/* Used in tsk->state again: */
-#define TASK_PARKED 0x0040
-#define TASK_DEAD 0x0080
-#define TASK_WAKEKILL 0x0100
-#define TASK_WAKING 0x0200
-#define TASK_NOLOAD 0x0400
-#define TASK_NEW 0x0800
-/* RT specific auxilliary flag to mark RT lock waiters */
-#define TASK_RTLOCK_WAIT 0x1000
-#define TASK_STATE_MAX 0x2000
+#define TASK_PARKED 0x000040
+#define TASK_DEAD 0x000080
+#define TASK_WAKEKILL 0x000100
+#define TASK_WAKING 0x000200
+#define TASK_NOLOAD 0x000400
+#define TASK_NEW 0x000800
+#define TASK_FREEZABLE 0x001000
+#define __TASK_FREEZABLE_UNSAFE (0x002000 * IS_ENABLED(CONFIG_LOCKDEP))
+#define TASK_FROZEN 0x004000
+#define TASK_RTLOCK_WAIT 0x008000
+#define TASK_STATE_MAX 0x010000
+
+/*
+ * DO NOT ADD ANY NEW USERS !
+ */
+#define TASK_FREEZABLE_UNSAFE (TASK_FREEZABLE | __TASK_FREEZABLE_UNSAFE)

/* Convenience macros for the sake of set_current_state: */
#define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
@@ -1695,7 +1702,6 @@ extern struct pid *cad_pid;
#define PF_USED_MATH 0x00002000 /* If unset the fpu must be initialized before use */
#define PF_USED_ASYNC 0x00004000 /* Used async_schedule*(), used by module init */
#define PF_NOFREEZE 0x00008000 /* This thread should not be frozen */
-#define PF_FROZEN 0x00010000 /* Frozen for system suspend */
#define PF_KSWAPD 0x00020000 /* I am kswapd */
#define PF_MEMALLOC_NOFS 0x00040000 /* All allocation requests will inherit GFP_NOFS */
#define PF_MEMALLOC_NOIO 0x00080000 /* All allocation requests will inherit GFP_NOIO */
@@ -1707,7 +1713,6 @@ extern struct pid *cad_pid;
#define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */
#define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */
#define PF_MEMALLOC_PIN 0x10000000 /* Allocation context constrained to zones which allow long term pinning. */
-#define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */
#define PF_SUSPEND_TASK 0x80000000 /* This thread called freeze_processes() and should not be frozen */

/*
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -265,7 +265,7 @@ int rpc_malloc(struct rpc_task *);
void rpc_free(struct rpc_task *);
int rpciod_up(void);
void rpciod_down(void);
-int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *);
+int rpc_wait_for_completion_task(struct rpc_task *task);
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
struct net;
void rpc_show_tasks(struct net *);
@@ -276,11 +276,6 @@ extern struct workqueue_struct *rpciod_w
extern struct workqueue_struct *xprtiod_workqueue;
void rpc_prepare_task(struct rpc_task *task);

-static inline int rpc_wait_for_completion_task(struct rpc_task *task)
-{
- return __rpc_wait_for_completion_task(task, NULL);
-}
-
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
static inline const char * rpc_qname(const struct rpc_wait_queue *q)
{
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -335,8 +335,8 @@ do { \
} while (0)

#define __wait_event_freezable(wq_head, condition) \
- ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
- freezable_schedule())
+ ___wait_event(wq_head, condition, (TASK_INTERRUPTIBLE|TASK_FREEZABLE), \
+ 0, 0, schedule())

/**
* wait_event_freezable - sleep (or freeze) until a condition gets true
@@ -394,8 +394,8 @@ do { \

#define __wait_event_freezable_timeout(wq_head, condition, timeout) \
___wait_event(wq_head, ___wait_cond_timeout(condition), \
- TASK_INTERRUPTIBLE, 0, timeout, \
- __ret = freezable_schedule_timeout(__ret))
+ (TASK_INTERRUPTIBLE|TASK_FREEZABLE), 0, timeout, \
+ __ret = schedule_timeout(__ret))

/*
* like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
@@ -615,8 +615,8 @@ do { \

#define __wait_event_freezable_exclusive(wq, condition) \
- ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
- freezable_schedule())
+ ___wait_event(wq, condition, (TASK_INTERRUPTIBLE|TASK_FREEZABLE), 1, 0,\
+ schedule())

#define wait_event_freezable_exclusive(wq, condition) \
({ \
@@ -905,6 +905,34 @@ extern int do_wait_intr_irq(wait_queue_h
__ret; \
})

+#define __wait_event_state(wq, condition, state) \
+ ___wait_event(wq, condition, state, 0, 0, schedule())
+
+/**
+ * wait_event_state - sleep until a condition gets true
+ * @wq_head: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ * @state: state to sleep in
+ *
+ * The process is put to sleep (@state) until the @condition evaluates to true
+ * or a signal is received. The @condition is checked each time the waitqueue
+ * @wq_head is woken up.
+ *
+ * wake_up() has to be called after changing any variable that could
+ * change the result of the wait condition.
+ *
+ * The function will return -ERESTARTSYS if it was interrupted by a
+ * signal and 0 if @condition evaluated to true.
+ */
+#define wait_event_state(wq_head, condition, state) \
+({ \
+ int __ret = 0; \
+ might_sleep(); \
+ if (!(condition)) \
+ __ret = __wait_event_state(wq_head, condition, state); \
+ __ret; \
+})
+
#define __wait_event_killable_timeout(wq_head, condition, timeout) \
___wait_event(wq_head, ___wait_cond_timeout(condition), \
TASK_KILLABLE, 0, timeout, \
--- a/kernel/cgroup/legacy_freezer.c
+++ b/kernel/cgroup/legacy_freezer.c
@@ -113,7 +113,7 @@ static int freezer_css_online(struct cgr

if (parent && (parent->state & CGROUP_FREEZING)) {
freezer->state |= CGROUP_FREEZING_PARENT | CGROUP_FROZEN;
- atomic_inc(&system_freezing_cnt);
+ static_branch_inc(&freezer_active);
}

mutex_unlock(&freezer_mutex);
@@ -134,7 +134,7 @@ static void freezer_css_offline(struct c
mutex_lock(&freezer_mutex);

if (freezer->state & CGROUP_FREEZING)
- atomic_dec(&system_freezing_cnt);
+ static_branch_dec(&freezer_active);

freezer->state = 0;

@@ -179,6 +179,7 @@ static void freezer_attach(struct cgroup
__thaw_task(task);
} else {
freeze_task(task);
+
/* clear FROZEN and propagate upwards */
while (freezer && (freezer->state & CGROUP_FROZEN)) {
freezer->state &= ~CGROUP_FROZEN;
@@ -271,16 +272,8 @@ static void update_if_frozen(struct cgro
css_task_iter_start(css, 0, &it);

while ((task = css_task_iter_next(&it))) {
- if (freezing(task)) {
- /*
- * freezer_should_skip() indicates that the task
- * should be skipped when determining freezing
- * completion. Consider it frozen in addition to
- * the usual frozen condition.
- */
- if (!frozen(task) && !freezer_should_skip(task))
- goto out_iter_end;
- }
+ if (freezing(task) && !frozen(task))
+ goto out_iter_end;
}

freezer->state |= CGROUP_FROZEN;
@@ -357,7 +350,7 @@ static void freezer_apply_state(struct f

if (freeze) {
if (!(freezer->state & CGROUP_FREEZING))
- atomic_inc(&system_freezing_cnt);
+ static_branch_inc(&freezer_active);
freezer->state |= state;
freeze_cgroup(freezer);
} else {
@@ -366,9 +359,9 @@ static void freezer_apply_state(struct f
freezer->state &= ~state;

if (!(freezer->state & CGROUP_FREEZING)) {
- if (was_freezing)
- atomic_dec(&system_freezing_cnt);
freezer->state &= ~CGROUP_FROZEN;
+ if (was_freezing)
+ static_branch_dec(&freezer_active);
unfreeze_cgroup(freezer);
}
}
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -469,10 +469,10 @@ static void exit_mm(void)
complete(&core_state->startup);

for (;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
+ set_current_state(TASK_UNINTERRUPTIBLE|TASK_FREEZABLE);
if (!self.task) /* see coredump_finish() */
break;
- freezable_schedule();
+ schedule();
}
__set_current_state(TASK_RUNNING);
mmap_read_lock(mm);
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1348,13 +1348,12 @@ static void complete_vfork_done(struct t
static int wait_for_vfork_done(struct task_struct *child,
struct completion *vfork)
{
+ unsigned int state = TASK_UNINTERRUPTIBLE|TASK_KILLABLE|TASK_FREEZABLE;
int killed;

- freezer_do_not_count();
cgroup_enter_frozen();
- killed = wait_for_completion_killable(vfork);
+ killed = wait_for_completion_state(vfork, state);
cgroup_leave_frozen(false);
- freezer_count();

if (killed) {
task_lock(child);
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -13,10 +13,11 @@
#include <linux/kthread.h>

/* total number of freezing conditions in effect */
-atomic_t system_freezing_cnt = ATOMIC_INIT(0);
-EXPORT_SYMBOL(system_freezing_cnt);
+DEFINE_STATIC_KEY_FALSE(freezer_active);
+EXPORT_SYMBOL(freezer_active);

-/* indicate whether PM freezing is in effect, protected by
+/*
+ * indicate whether PM freezing is in effect, protected by
* system_transition_mutex
*/
bool pm_freezing;
@@ -29,7 +30,7 @@ static DEFINE_SPINLOCK(freezer_lock);
* freezing_slow_path - slow path for testing whether a task needs to be frozen
* @p: task to be tested
*
- * This function is called by freezing() if system_freezing_cnt isn't zero
+ * This function is called by freezing() if freezer_active isn't zero
* and tests whether @p needs to enter and stay in frozen state. Can be
* called under any context. The freezers are responsible for ensuring the
* target tasks see the updated state.
@@ -52,41 +53,40 @@ bool freezing_slow_path(struct task_stru
}
EXPORT_SYMBOL(freezing_slow_path);

+bool frozen(struct task_struct *p)
+{
+ return READ_ONCE(p->__state) & TASK_FROZEN;
+}
+
/* Refrigerator is place where frozen processes are stored :-). */
bool __refrigerator(bool check_kthr_stop)
{
- /* Hmm, should we be allowed to suspend when there are realtime
- processes around? */
+ unsigned int state = get_current_state();
bool was_frozen = false;
- unsigned int save = get_current_state();

pr_debug("%s entered refrigerator\n", current->comm);

+ WARN_ON_ONCE(state && !(state & TASK_NORMAL));
+
for (;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
+ bool freeze;
+
+ set_current_state(TASK_FROZEN);

spin_lock_irq(&freezer_lock);
- current->flags |= PF_FROZEN;
- if (!freezing(current) ||
- (check_kthr_stop && kthread_should_stop()))
- current->flags &= ~PF_FROZEN;
+ freeze = freezing(current) && !(check_kthr_stop && kthread_should_stop());
spin_unlock_irq(&freezer_lock);

- if (!(current->flags & PF_FROZEN))
+ if (!freeze)
break;
+
was_frozen = true;
schedule();
}
+ __set_current_state(TASK_RUNNING);

pr_debug("%s left refrigerator\n", current->comm);

- /*
- * Restore saved task state before returning. The mb'd version
- * needs to be used; otherwise, it might silently break
- * synchronization which depends on ordered task state change.
- */
- set_current_state(save);
-
return was_frozen;
}
EXPORT_SYMBOL(__refrigerator);
@@ -101,6 +101,37 @@ static void fake_signal_wake_up(struct t
}
}

+static inline unsigned int __can_freeze(struct task_struct *p)
+{
+ unsigned int state = READ_ONCE(p->__state);
+
+ if (!(state & (TASK_FREEZABLE | __TASK_STOPPED | __TASK_TRACED)))
+ return 0;
+
+ /*
+ * Only TASK_NORMAL can be augmented with TASK_FREEZABLE, since they
+ * can suffer spurious wakeups.
+ */
+ if (state & TASK_FREEZABLE)
+ WARN_ON_ONCE(!(state & TASK_NORMAL));
+
+#ifdef CONFIG_LOCKDEP
+ /*
+ * It's dangerous to freeze with locks held; there be dragons there.
+ */
+ if (!(state & __TASK_FREEZABLE_UNSAFE))
+ WARN_ON_ONCE(debug_locks && p->lockdep_depth);
+#endif
+
+ return TASK_FROZEN;
+}
+
+/* See task_cond_set_special_state(); serializes against ttwu() */
+static bool __freeze_task(struct task_struct *p)
+{
+ return task_cond_set_special_state(p, __can_freeze(p));
+}
+
/**
* freeze_task - send a freeze request to given task
* @p: task to send the request to
@@ -116,20 +147,8 @@ bool freeze_task(struct task_struct *p)
{
unsigned long flags;

- /*
- * This check can race with freezer_do_not_count, but worst case that
- * will result in an extra wakeup being sent to the task. It does not
- * race with freezer_count(), the barriers in freezer_count() and
- * freezer_should_skip() ensure that either freezer_count() sees
- * freezing == true in try_to_freeze() and freezes, or
- * freezer_should_skip() sees !PF_FREEZE_SKIP and freezes the task
- * normally.
- */
- if (freezer_should_skip(p))
- return false;
-
spin_lock_irqsave(&freezer_lock, flags);
- if (!freezing(p) || frozen(p)) {
+ if (!freezing(p) || frozen(p) || __freeze_task(p)) {
spin_unlock_irqrestore(&freezer_lock, flags);
return false;
}
@@ -137,19 +156,58 @@ bool freeze_task(struct task_struct *p)
if (!(p->flags & PF_KTHREAD))
fake_signal_wake_up(p);
else
- wake_up_state(p, TASK_INTERRUPTIBLE);
+ wake_up_state(p, TASK_NORMAL);

spin_unlock_irqrestore(&freezer_lock, flags);
return true;
}

+/*
+ * The special task states (TASK_STOPPED, TASK_TRACED) keep their canonical
+ * state in p->jobctl and p->ptrace respectively. If either of them got a
+ * wakeup that was missed because TASK_FROZEN, then their canonical state
+ * reflects that and the below will refuse to restore the special state and
+ * instead issue the wakeup.
+ */
+static inline unsigned int __thaw_special(struct task_struct *p)
+{
+ unsigned int state = 0;
+
+ if (p->ptrace & PT_STOPPED) {
+ state = __TASK_TRACED;
+
+ if (p->ptrace & PT_STOPPED_FATAL) {
+ state |= TASK_WAKEKILL;
+ if (__fatal_signal_pending(p))
+ state = 0;
+ }
+
+ } else if ((p->jobctl & JOBCTL_STOP_PENDING) &&
+ !__fatal_signal_pending(p)) {
+
+ state = TASK_STOPPED;
+ }
+
+ return state;
+}
+
void __thaw_task(struct task_struct *p)
{
- unsigned long flags;
+ unsigned long flags, flags2;

spin_lock_irqsave(&freezer_lock, flags);
- if (frozen(p))
- wake_up_process(p);
+ if (WARN_ON_ONCE(freezing(p)))
+ goto unlock;
+
+ if (lock_task_sighand(p, &flags2)) {
+ bool ret = task_cond_set_special_state(p, __thaw_special(p));
+ unlock_task_sighand(p, &flags2);
+ if (ret)
+ goto unlock;
+ }
+
+ wake_up_state(p, TASK_FROZEN);
+unlock:
spin_unlock_irqrestore(&freezer_lock, flags);
}

--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2832,7 +2832,7 @@ static void futex_wait_queue_me(struct f
* queue_me() calls spin_unlock() upon completion, both serializing
* access to the hash list and forcing another memory barrier.
*/
- set_current_state(TASK_INTERRUPTIBLE);
+ set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
queue_me(q, hb);

/* Arm the timer */
@@ -2850,7 +2850,7 @@ static void futex_wait_queue_me(struct f
* is no timeout, or if it has yet to expire.
*/
if (!timeout || timeout->task)
- freezable_schedule();
+ schedule();
}
__set_current_state(TASK_RUNNING);
}
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -93,8 +93,8 @@ static void check_hung_task(struct task_
* Ensure the task is not frozen.
* Also, skip vfork and any other user process that freezer should skip.
*/
- if (unlikely(t->flags & (PF_FROZEN | PF_FREEZER_SKIP)))
- return;
+ if (unlikely(READ_ONCE(t->__state) & (TASK_FREEZABLE | TASK_FROZEN)))
+ return;

/*
* When a freshly created task is scheduled once, changes its state to
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -24,7 +24,7 @@
unsigned int lock_system_sleep(void)
{
unsigned int flags = current->flags;
- current->flags |= PF_FREEZER_SKIP;
+ current->flags |= PF_NOFREEZE;
mutex_lock(&system_transition_mutex);
return flags;
}
@@ -48,8 +48,8 @@ void unlock_system_sleep(unsigned int fl
* Which means, if we use try_to_freeze() here, it would make them
* enter the refrigerator, thus causing hibernation to lockup.
*/
- if (!(flags & PF_FREEZER_SKIP))
- current->flags &= ~PF_FREEZER_SKIP;
+ if (!(flags & PF_NOFREEZE))
+ current->flags &= ~PF_NOFREEZE;
mutex_unlock(&system_transition_mutex);
}
EXPORT_SYMBOL_GPL(unlock_system_sleep);
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -53,8 +53,7 @@ static int try_to_freeze_tasks(bool user
if (p == current || !freeze_task(p))
continue;

- if (!freezer_should_skip(p))
- todo++;
+ todo++;
}
read_unlock(&tasklist_lock);

@@ -99,8 +98,7 @@ static int try_to_freeze_tasks(bool user
if (!wakeup || pm_debug_messages_on) {
read_lock(&tasklist_lock);
for_each_process_thread(g, p) {
- if (p != current && !freezer_should_skip(p)
- && freezing(p) && !frozen(p))
+ if (p != current && freezing(p) && !frozen(p))
sched_show_task(p);
}
read_unlock(&tasklist_lock);
@@ -132,7 +130,7 @@ int freeze_processes(void)
current->flags |= PF_SUSPEND_TASK;

if (!pm_freezing)
- atomic_inc(&system_freezing_cnt);
+ static_branch_inc(&freezer_active);

pm_wakeup_clear(true);
pr_info("Freezing user space processes ... ");
@@ -193,7 +191,7 @@ void thaw_processes(void)

trace_suspend_resume(TPS("thaw_processes"), 0, true);
if (pm_freezing)
- atomic_dec(&system_freezing_cnt);
+ static_branch_dec(&freezer_active);
pm_freezing = false;
pm_nosig_freezing = false;

--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -282,7 +282,7 @@ static int ptrace_check_attach(struct ta
read_unlock(&tasklist_lock);

if (!ret && !ignore_state) {
- if (!wait_task_inactive(child, __TASK_TRACED)) { // XXX mooo!!!
+ if (!wait_task_inactive(child, __TASK_TRACED | TASK_FREEZABLE)) {
/*
* This can only happen if may_ptrace_stop() fails and
* ptrace_stop() changes ->state back to TASK_RUNNING,
--- a/kernel/sched/completion.c
+++ b/kernel/sched/completion.c
@@ -247,6 +247,15 @@ int __sched wait_for_completion_killable
}
EXPORT_SYMBOL(wait_for_completion_killable);

+int __sched wait_for_completion_state(struct completion *x, unsigned int state)
+{
+ long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, state);
+ if (t == -ERESTARTSYS)
+ return t;
+ return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_state);
+
/**
* wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
* @x: holds the state of this particular completion
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3162,6 +3162,19 @@ int migrate_swap(struct task_struct *cur
}
#endif /* CONFIG_NUMA_BALANCING */

+static inline __wti_match(struct task_struct *p, unsigned int match_state)
+{
+ unsigned int state = READ_ONCE(p->__state);
+
+ if ((match_state & TASK_FREEZABLE) && state == TASK_FROZEN)
+ return true;
+
+ if (state == (match_state & ~TASK_FREEZABLE))
+ return true;
+
+ return false;
+}
+
/*
* wait_task_inactive - wait for a thread to unschedule.
*
@@ -3206,7 +3219,7 @@ unsigned long wait_task_inactive(struct
* is actually now running somewhere else!
*/
while (task_running(rq, p)) {
- if (match_state && unlikely(READ_ONCE(p->__state) != match_state))
+ if (match_state && __wti_match(p, match_state))
return 0;
cpu_relax();
}
@@ -3221,7 +3234,7 @@ unsigned long wait_task_inactive(struct
running = task_running(rq, p);
queued = task_on_rq_queued(p);
ncsw = 0;
- if (!match_state || READ_ONCE(p->__state) == match_state)
+ if (!match_state || __wti_match(p, match_state))
ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
task_rq_unlock(rq, p, &rf);

@@ -6154,7 +6167,7 @@ static void __sched notrace __schedule(u
prev->sched_contributes_to_load =
(prev_state & TASK_UNINTERRUPTIBLE) &&
!(prev_state & TASK_NOLOAD) &&
- !(prev->flags & PF_FROZEN);
+ !(prev_state & TASK_FROZEN);

if (prev->sched_contributes_to_load)
rq->nr_uninterruptible++;
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2299,7 +2299,7 @@ static void ptrace_stop(int exit_code, i
read_unlock(&tasklist_lock);
cgroup_enter_frozen();
preempt_enable_no_resched();
- freezable_schedule();
+ schedule();
cgroup_leave_frozen(true);
} else {
/*
@@ -2479,7 +2479,7 @@ static bool do_signal_stop(int signr)

/* Now we don't run again until woken by SIGCONT or SIGKILL */
cgroup_enter_frozen();
- freezable_schedule();
+ schedule();
return true;
} else {
/*
@@ -2555,11 +2555,11 @@ static void do_freezer_trap(void)
* immediately (if there is a non-fatal signal pending), and
* put the task into sleep.
*/
- __set_current_state(TASK_INTERRUPTIBLE);
+ __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
clear_thread_flag(TIF_SIGPENDING);
spin_unlock_irq(&current->sighand->siglock);
cgroup_enter_frozen();
- freezable_schedule();
+ schedule();
}

static int ptrace_signal(int signr, kernel_siginfo_t *info)
@@ -3608,9 +3608,9 @@ static int do_sigtimedwait(const sigset_
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);

- __set_current_state(TASK_INTERRUPTIBLE);
- ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
- HRTIMER_MODE_REL);
+ __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+ ret = schedule_hrtimeout_range(to, tsk->timer_slack_ns,
+ HRTIMER_MODE_REL);
spin_lock_irq(&tsk->sighand->siglock);
__set_task_blocked(tsk, &tsk->real_blocked);
sigemptyset(&tsk->real_blocked);
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -2037,11 +2037,11 @@ static int __sched do_nanosleep(struct h
struct restart_block *restart;

do {
- set_current_state(TASK_INTERRUPTIBLE);
+ set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
hrtimer_sleeper_start_expires(t, mode);

if (likely(t->task))
- freezable_schedule();
+ schedule();

hrtimer_cancel(&t->timer);
mode = HRTIMER_MODE_ABS;
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -404,6 +404,7 @@ EXPORT_SYMBOL(call_usermodehelper_setup)
*/
int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
{
+ unsigned int state = TASK_UNINTERRUPTIBLE;
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;

@@ -437,25 +438,22 @@ int call_usermodehelper_exec(struct subp
if (wait == UMH_NO_WAIT) /* task has freed sub_info */
goto unlock;

+ if (wait & UMH_KILLABLE)
+ state |= TASK_KILLABLE;
+
if (wait & UMH_FREEZABLE)
- freezer_do_not_count();
+ state |= TASK_FREEZABLE;

- if (wait & UMH_KILLABLE) {
- retval = wait_for_completion_killable(&done);
- if (!retval)
- goto wait_done;
+ retval = wait_for_completion_state(&done, state);
+ if (!retval)
+ goto wait_done;

+ if (wait & UMH_KILLABLE) {
/* umh_complete() will see NULL and free sub_info */
if (xchg(&sub_info->complete, NULL))
goto unlock;
- /* fallthrough, umh_complete() was already called */
}

- wait_for_completion(&done);
-
- if (wait & UMH_FREEZABLE)
- freezer_count();
-
wait_done:
retval = sub_info->retval;
out:
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -793,8 +793,8 @@ static void khugepaged_alloc_sleep(void)
DEFINE_WAIT(wait);

add_wait_queue(&khugepaged_wait, &wait);
- freezable_schedule_timeout_interruptible(
- msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
+ __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+ schedule_timeout(msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
remove_wait_queue(&khugepaged_wait, &wait);
}

--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -268,7 +268,7 @@ EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue

static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode)
{
- freezable_schedule_unsafe();
+ schedule();
if (signal_pending_state(mode, current))
return -ERESTARTSYS;
return 0;
@@ -324,14 +324,12 @@ static int rpc_complete_task(struct rpc_
* to enforce taking of the wq->lock and hence avoid races with
* rpc_complete_task().
*/
-int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *action)
+int rpc_wait_for_completion_task(struct rpc_task *task)
{
- if (action == NULL)
- action = rpc_wait_bit_killable;
return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
- action, TASK_KILLABLE);
+ rpc_wait_bit_killable, TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
}
-EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
+EXPORT_SYMBOL_GPL(rpc_wait_for_completion_task);

/*
* Make an RPC task runnable.
@@ -938,7 +936,7 @@ static void __rpc_execute(struct rpc_tas
trace_rpc_task_sync_sleep(task, task->tk_action);
status = out_of_line_wait_on_bit(&task->tk_runstate,
RPC_TASK_QUEUED, rpc_wait_bit_killable,
- TASK_KILLABLE);
+ TASK_KILLABLE|TASK_FREEZABLE);
if (status < 0) {
/*
* When a sync task receives a signal, it exits with
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2442,13 +2442,14 @@ static long unix_stream_data_wait(struct
struct sk_buff *last, unsigned int last_len,
bool freezable)
{
+ unsigned int state = TASK_INTERRUPTIBLE | freezable * TASK_FREEZABLE;
struct sk_buff *tail;
DEFINE_WAIT(wait);

unix_state_lock(sk);

for (;;) {
- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ prepare_to_wait(sk_sleep(sk), &wait, state);

tail = skb_peek_tail(&sk->sk_receive_queue);
if (tail != last ||
@@ -2461,10 +2462,7 @@ static long unix_stream_data_wait(struct

sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
unix_state_unlock(sk);
- if (freezable)
- timeo = freezable_schedule_timeout(timeo);
- else
- timeo = schedule_timeout(timeo);
+ timeo = schedule_timeout(timeo);
unix_state_lock(sk);

if (sock_flag(sk, SOCK_DEAD))