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SubjectRe: Linux 4.19.172
Date
diff --git a/Documentation/device-mapper/dm-integrity.txt b/Documentation/device-mapper/dm-integrity.txt
index 297251b0d2d5..bf6af2ade0a6 100644
--- a/Documentation/device-mapper/dm-integrity.txt
+++ b/Documentation/device-mapper/dm-integrity.txt
@@ -146,6 +146,13 @@ block_size:number
Supported values are 512, 1024, 2048 and 4096 bytes. If not
specified the default block size is 512 bytes.

+legacy_recalculate
+ Allow recalculating of volumes with HMAC keys. This is disabled by
+ default for security reasons - an attacker could modify the volume,
+ set recalc_sector to zero, and the kernel would not detect the
+ modification.
+
+
The journal mode (D/J), buffer_sectors, journal_watermark, commit_time can
be changed when reloading the target (load an inactive table and swap the
tables with suspend and resume). The other arguments should not be changed
diff --git a/Makefile b/Makefile
index 335b015c5c9b..7da0ddd65052 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
VERSION = 4
PATCHLEVEL = 19
-SUBLEVEL = 171
+SUBLEVEL = 172
EXTRAVERSION =
NAME = "People's Front"

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index 3b78dcda4736..874caed72390 100644
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -650,9 +650,8 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,

spin_lock_irqsave(&mvpwm->lock, flags);

- val = (unsigned long long)
- readl_relaxed(mvebu_pwmreg_blink_on_duration(mvpwm));
- val *= NSEC_PER_SEC;
+ u = readl_relaxed(mvebu_pwmreg_blink_on_duration(mvpwm));
+ val = (unsigned long long) u * NSEC_PER_SEC;
do_div(val, mvpwm->clk_rate);
if (val > UINT_MAX)
state->duty_cycle = UINT_MAX;
@@ -661,21 +660,17 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
else
state->duty_cycle = 1;

- val = (unsigned long long)
- readl_relaxed(mvebu_pwmreg_blink_off_duration(mvpwm));
+ val = (unsigned long long) u; /* on duration */
+ /* period = on + off duration */
+ val += readl_relaxed(mvebu_pwmreg_blink_off_duration(mvpwm));
val *= NSEC_PER_SEC;
do_div(val, mvpwm->clk_rate);
- if (val < state->duty_cycle) {
+ if (val > UINT_MAX)
+ state->period = UINT_MAX;
+ else if (val)
+ state->period = val;
+ else
state->period = 1;
- } else {
- val -= state->duty_cycle;
- if (val > UINT_MAX)
- state->period = UINT_MAX;
- else if (val)
- state->period = val;
- else
- state->period = 1;
- }

regmap_read(mvchip->regs, GPIO_BLINK_EN_OFF + mvchip->offset, &u);
if (u)
diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 523014f2c0eb..8006732b8f42 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -150,9 +150,9 @@ static int wacom_wac_pen_serial_enforce(struct hid_device *hdev,
}

if (flush)
- wacom_wac_queue_flush(hdev, &wacom_wac->pen_fifo);
+ wacom_wac_queue_flush(hdev, wacom_wac->pen_fifo);
else if (insert)
- wacom_wac_queue_insert(hdev, &wacom_wac->pen_fifo,
+ wacom_wac_queue_insert(hdev, wacom_wac->pen_fifo,
raw_data, report_size);

return insert && !flush;
@@ -1251,7 +1251,7 @@ static void wacom_devm_kfifo_release(struct device *dev, void *res)
static int wacom_devm_kfifo_alloc(struct wacom *wacom)
{
struct wacom_wac *wacom_wac = &wacom->wacom_wac;
- struct kfifo_rec_ptr_2 *pen_fifo = &wacom_wac->pen_fifo;
+ struct kfifo_rec_ptr_2 *pen_fifo;
int error;

pen_fifo = devres_alloc(wacom_devm_kfifo_release,
@@ -1268,6 +1268,7 @@ static int wacom_devm_kfifo_alloc(struct wacom *wacom)
}

devres_add(&wacom->hdev->dev, pen_fifo);
+ wacom_wac->pen_fifo = pen_fifo;

return 0;
}
diff --git a/drivers/hid/wacom_wac.h b/drivers/hid/wacom_wac.h
index f67d871841c0..46da97162ef4 100644
--- a/drivers/hid/wacom_wac.h
+++ b/drivers/hid/wacom_wac.h
@@ -344,7 +344,7 @@ struct wacom_wac {
struct input_dev *pen_input;
struct input_dev *touch_input;
struct input_dev *pad_input;
- struct kfifo_rec_ptr_2 pen_fifo;
+ struct kfifo_rec_ptr_2 *pen_fifo;
int pid;
int num_contacts_left;
u8 bt_features;
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 1917051b512f..cffd42317272 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -240,6 +240,7 @@ struct dm_integrity_c {

bool journal_uptodate;
bool just_formatted;
+ bool legacy_recalculate;

struct alg_spec internal_hash_alg;
struct alg_spec journal_crypt_alg;
@@ -345,6 +346,14 @@ static int dm_integrity_failed(struct dm_integrity_c *ic)
return READ_ONCE(ic->failed);
}

+static bool dm_integrity_disable_recalculate(struct dm_integrity_c *ic)
+{
+ if ((ic->internal_hash_alg.key || ic->journal_mac_alg.key) &&
+ !ic->legacy_recalculate)
+ return true;
+ return false;
+}
+
static commit_id_t dm_integrity_commit_id(struct dm_integrity_c *ic, unsigned i,
unsigned j, unsigned char seq)
{
@@ -2503,6 +2512,7 @@ static void dm_integrity_status(struct dm_target *ti, status_type_t type,
arg_count += !!ic->internal_hash_alg.alg_string;
arg_count += !!ic->journal_crypt_alg.alg_string;
arg_count += !!ic->journal_mac_alg.alg_string;
+ arg_count += ic->legacy_recalculate;
DMEMIT("%s %llu %u %c %u", ic->dev->name, (unsigned long long)ic->start,
ic->tag_size, ic->mode, arg_count);
if (ic->meta_dev)
@@ -2516,6 +2526,8 @@ static void dm_integrity_status(struct dm_target *ti, status_type_t type,
DMEMIT(" buffer_sectors:%u", 1U << ic->log2_buffer_sectors);
DMEMIT(" journal_watermark:%u", (unsigned)watermark_percentage);
DMEMIT(" commit_time:%u", ic->autocommit_msec);
+ if (ic->legacy_recalculate)
+ DMEMIT(" legacy_recalculate");

#define EMIT_ALG(a, n) \
do { \
@@ -3118,7 +3130,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
unsigned extra_args;
struct dm_arg_set as;
static const struct dm_arg _args[] = {
- {0, 15, "Invalid number of feature args"},
+ {0, 12, "Invalid number of feature args"},
};
unsigned journal_sectors, interleave_sectors, buffer_sectors, journal_watermark, sync_msec;
bool recalculate;
@@ -3248,6 +3260,8 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
goto bad;
} else if (!strcmp(opt_string, "recalculate")) {
recalculate = true;
+ } else if (!strcmp(opt_string, "legacy_recalculate")) {
+ ic->legacy_recalculate = true;
} else {
r = -EINVAL;
ti->error = "Invalid argument";
@@ -3523,6 +3537,14 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
}
}

+ if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING) &&
+ le64_to_cpu(ic->sb->recalc_sector) < ic->provided_data_sectors &&
+ dm_integrity_disable_recalculate(ic)) {
+ ti->error = "Recalculating with HMAC is disabled for security reasons - if you really need it, use the argument \"legacy_recalculate\"";
+ r = -EOPNOTSUPP;
+ goto bad;
+ }
+
ic->bufio = dm_bufio_client_create(ic->meta_dev ? ic->meta_dev->bdev : ic->dev->bdev,
1U << (SECTOR_SHIFT + ic->log2_buffer_sectors), 1, 0, NULL, NULL);
if (IS_ERR(ic->bufio)) {
diff --git a/fs/exec.c b/fs/exec.c
index 52788644c4af..6eea921a7e72 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1011,7 +1011,7 @@ static int exec_mmap(struct mm_struct *mm)
/* Notify parent that we're no longer interested in the old VM */
tsk = current;
old_mm = current->mm;
- mm_release(tsk, old_mm);
+ exec_mm_release(tsk, old_mm);

if (old_mm) {
sync_mm_rss(old_mm);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b2a9c746f8ce..edeb837081c8 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5209,7 +5209,7 @@ static int other_inode_match(struct inode * inode, unsigned long ino,
(inode->i_state & I_DIRTY_TIME)) {
struct ext4_inode_info *ei = EXT4_I(inode);

- inode->i_state &= ~(I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED);
+ inode->i_state &= ~I_DIRTY_TIME;
spin_unlock(&inode->i_lock);

spin_lock(&ei->i_raw_lock);
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 15216b440880..f2d0c4acb3cb 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1157,7 +1157,7 @@ static bool inode_dirtied_after(struct inode *inode, unsigned long t)
*/
static int move_expired_inodes(struct list_head *delaying_queue,
struct list_head *dispatch_queue,
- int flags, unsigned long dirtied_before)
+ unsigned long dirtied_before)
{
LIST_HEAD(tmp);
struct list_head *pos, *node;
@@ -1173,8 +1173,6 @@ static int move_expired_inodes(struct list_head *delaying_queue,
list_move(&inode->i_io_list, &tmp);
moved++;
spin_lock(&inode->i_lock);
- if (flags & EXPIRE_DIRTY_ATIME)
- inode->i_state |= I_DIRTY_TIME_EXPIRED;
inode->i_state |= I_SYNC_QUEUED;
spin_unlock(&inode->i_lock);
if (sb_is_blkdev_sb(inode->i_sb))
@@ -1222,11 +1220,11 @@ static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work,

assert_spin_locked(&wb->list_lock);
list_splice_init(&wb->b_more_io, &wb->b_io);
- moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, 0, dirtied_before);
+ moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, dirtied_before);
if (!work->for_sync)
time_expire_jif = jiffies - dirtytime_expire_interval * HZ;
moved += move_expired_inodes(&wb->b_dirty_time, &wb->b_io,
- EXPIRE_DIRTY_ATIME, time_expire_jif);
+ time_expire_jif);
if (moved)
wb_io_lists_populated(wb);
trace_writeback_queue_io(wb, work, dirtied_before, moved);
@@ -1394,26 +1392,26 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
ret = err;
}

+ /*
+ * If the inode has dirty timestamps and we need to write them, call
+ * mark_inode_dirty_sync() to notify the filesystem about it and to
+ * change I_DIRTY_TIME into I_DIRTY_SYNC.
+ */
+ if ((inode->i_state & I_DIRTY_TIME) &&
+ (wbc->sync_mode == WB_SYNC_ALL || wbc->for_sync ||
+ time_after(jiffies, inode->dirtied_time_when +
+ dirtytime_expire_interval * HZ))) {
+ trace_writeback_lazytime(inode);
+ mark_inode_dirty_sync(inode);
+ }
+
/*
* Some filesystems may redirty the inode during the writeback
* due to delalloc, clear dirty metadata flags right before
* write_inode()
*/
spin_lock(&inode->i_lock);
-
dirty = inode->i_state & I_DIRTY;
- if (inode->i_state & I_DIRTY_TIME) {
- if ((dirty & I_DIRTY_INODE) ||
- wbc->sync_mode == WB_SYNC_ALL ||
- unlikely(inode->i_state & I_DIRTY_TIME_EXPIRED) ||
- unlikely(time_after(jiffies,
- (inode->dirtied_time_when +
- dirtytime_expire_interval * HZ)))) {
- dirty |= I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED;
- trace_writeback_lazytime(inode);
- }
- } else
- inode->i_state &= ~I_DIRTY_TIME_EXPIRED;
inode->i_state &= ~dirty;

/*
@@ -1434,8 +1432,6 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)

spin_unlock(&inode->i_lock);

- if (dirty & I_DIRTY_TIME)
- mark_inode_dirty_sync(inode);
/* Don't write the inode if only I_DIRTY_PAGES was set */
if (dirty & ~I_DIRTY_PAGES) {
int err = write_inode(inode, wbc);
diff --git a/fs/xfs/xfs_trans_inode.c b/fs/xfs/xfs_trans_inode.c
index ae453dd236a6..6fcdf7e449fe 100644
--- a/fs/xfs/xfs_trans_inode.c
+++ b/fs/xfs/xfs_trans_inode.c
@@ -99,9 +99,9 @@ xfs_trans_log_inode(
* to log the timestamps, or will clear already cleared fields in the
* worst case.
*/
- if (inode->i_state & (I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED)) {
+ if (inode->i_state & I_DIRTY_TIME) {
spin_lock(&inode->i_lock);
- inode->i_state &= ~(I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED);
+ inode->i_state &= ~I_DIRTY_TIME;
spin_unlock(&inode->i_lock);
}

diff --git a/include/linux/compat.h b/include/linux/compat.h
index de0c13bdcd2c..189d0e111d57 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -445,8 +445,6 @@ struct compat_kexec_segment;
struct compat_mq_attr;
struct compat_msgbuf;

-extern void compat_exit_robust_list(struct task_struct *curr);
-
#define BITS_PER_COMPAT_LONG (8*sizeof(compat_long_t))

#define BITS_TO_COMPAT_LONGS(bits) DIV_ROUND_UP(bits, BITS_PER_COMPAT_LONG)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 876bfb6df06a..b6a955ba6173 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2071,7 +2071,6 @@ static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
#define I_DIO_WAKEUP (1 << __I_DIO_WAKEUP)
#define I_LINKABLE (1 << 10)
#define I_DIRTY_TIME (1 << 11)
-#define I_DIRTY_TIME_EXPIRED (1 << 12)
#define I_WB_SWITCH (1 << 13)
#define I_OVL_INUSE (1 << 14)
#define I_CREATING (1 << 15)
diff --git a/include/linux/futex.h b/include/linux/futex.h
index a61bf436dcf3..b70df27d7e85 100644
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -2,7 +2,9 @@
#ifndef _LINUX_FUTEX_H
#define _LINUX_FUTEX_H

+#include <linux/sched.h>
#include <linux/ktime.h>
+
#include <uapi/linux/futex.h>

struct inode;
@@ -51,15 +53,35 @@ union futex_key {
#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = 0ULL } }

#ifdef CONFIG_FUTEX
-extern void exit_robust_list(struct task_struct *curr);
+enum {
+ FUTEX_STATE_OK,
+ FUTEX_STATE_EXITING,
+ FUTEX_STATE_DEAD,
+};

-long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
- u32 __user *uaddr2, u32 val2, u32 val3);
-#else
-static inline void exit_robust_list(struct task_struct *curr)
+static inline void futex_init_task(struct task_struct *tsk)
{
+ tsk->robust_list = NULL;
+#ifdef CONFIG_COMPAT
+ tsk->compat_robust_list = NULL;
+#endif
+ INIT_LIST_HEAD(&tsk->pi_state_list);
+ tsk->pi_state_cache = NULL;
+ tsk->futex_state = FUTEX_STATE_OK;
+ mutex_init(&tsk->futex_exit_mutex);
}

+void futex_exit_recursive(struct task_struct *tsk);
+void futex_exit_release(struct task_struct *tsk);
+void futex_exec_release(struct task_struct *tsk);
+
+long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
+ u32 __user *uaddr2, u32 val2, u32 val3);
+#else
+static inline void futex_init_task(struct task_struct *tsk) { }
+static inline void futex_exit_recursive(struct task_struct *tsk) { }
+static inline void futex_exit_release(struct task_struct *tsk) { }
+static inline void futex_exec_release(struct task_struct *tsk) { }
static inline long do_futex(u32 __user *uaddr, int op, u32 val,
ktime_t *timeout, u32 __user *uaddr2,
u32 val2, u32 val3)
@@ -68,12 +90,4 @@ static inline long do_futex(u32 __user *uaddr, int op, u32 val,
}
#endif

-#ifdef CONFIG_FUTEX_PI
-extern void exit_pi_state_list(struct task_struct *curr);
-#else
-static inline void exit_pi_state_list(struct task_struct *curr)
-{
-}
-#endif
-
#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c69f308f3a53..5524cd5c6abe 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -996,6 +996,8 @@ struct task_struct {
#endif
struct list_head pi_state_list;
struct futex_pi_state *pi_state_cache;
+ struct mutex futex_exit_mutex;
+ unsigned int futex_state;
#endif
#ifdef CONFIG_PERF_EVENTS
struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];
@@ -1377,7 +1379,6 @@ extern struct pid *cad_pid;
*/
#define PF_IDLE 0x00000002 /* I am an IDLE thread */
#define PF_EXITING 0x00000004 /* Getting shut down */
-#define PF_EXITPIDONE 0x00000008 /* PI exit done on shut down */
#define PF_VCPU 0x00000010 /* I'm a virtual CPU */
#define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */
#define PF_FORKNOEXEC 0x00000040 /* Forked but didn't exec */
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 766bbe813861..8d3b7e731b74 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -119,8 +119,10 @@ extern struct mm_struct *get_task_mm(struct task_struct *task);
* succeeds.
*/
extern struct mm_struct *mm_access(struct task_struct *task, unsigned int mode);
-/* Remove the current tasks stale references to the old mm_struct */
-extern void mm_release(struct task_struct *, struct mm_struct *);
+/* Remove the current tasks stale references to the old mm_struct on exit() */
+extern void exit_mm_release(struct task_struct *, struct mm_struct *);
+/* Remove the current tasks stale references to the old mm_struct on exec() */
+extern void exec_mm_release(struct task_struct *, struct mm_struct *);

#ifdef CONFIG_MEMCG
extern void mm_update_next_owner(struct mm_struct *mm);
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 29d09755e5cf..146e7b3faa85 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -20,7 +20,6 @@
{I_CLEAR, "I_CLEAR"}, \
{I_SYNC, "I_SYNC"}, \
{I_DIRTY_TIME, "I_DIRTY_TIME"}, \
- {I_DIRTY_TIME_EXPIRED, "I_DIRTY_TIME_EXPIRED"}, \
{I_REFERENCED, "I_REFERENCED"} \
)

diff --git a/kernel/exit.c b/kernel/exit.c
index 65133ebddfad..908e7a33e1fc 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -498,7 +498,7 @@ static void exit_mm(void)
struct mm_struct *mm = current->mm;
struct core_state *core_state;

- mm_release(current, mm);
+ exit_mm_release(current, mm);
if (!mm)
return;
sync_mm_rss(mm);
@@ -818,32 +818,12 @@ void __noreturn do_exit(long code)
*/
if (unlikely(tsk->flags & PF_EXITING)) {
pr_alert("Fixing recursive fault but reboot is needed!\n");
- /*
- * We can do this unlocked here. The futex code uses
- * this flag just to verify whether the pi state
- * cleanup has been done or not. In the worst case it
- * loops once more. We pretend that the cleanup was
- * done as there is no way to return. Either the
- * OWNER_DIED bit is set by now or we push the blocked
- * task into the wait for ever nirwana as well.
- */
- tsk->flags |= PF_EXITPIDONE;
+ futex_exit_recursive(tsk);
set_current_state(TASK_UNINTERRUPTIBLE);
schedule();
}

exit_signals(tsk); /* sets PF_EXITING */
- /*
- * Ensure that all new tsk->pi_lock acquisitions must observe
- * PF_EXITING. Serializes against futex.c:attach_to_pi_owner().
- */
- smp_mb();
- /*
- * Ensure that we must observe the pi_state in exit_mm() ->
- * mm_release() -> exit_pi_state_list().
- */
- raw_spin_lock_irq(&tsk->pi_lock);
- raw_spin_unlock_irq(&tsk->pi_lock);

/* sync mm's RSS info before statistics gathering */
if (tsk->mm)
@@ -918,12 +898,6 @@ void __noreturn do_exit(long code)
* Make sure we are holding no locks:
*/
debug_check_no_locks_held();
- /*
- * We can do this unlocked here. The futex code uses this flag
- * just to verify whether the pi state cleanup has been done
- * or not. In the worst case it loops once more.
- */
- tsk->flags |= PF_EXITPIDONE;

if (tsk->io_context)
exit_io_context(tsk);
diff --git a/kernel/fork.c b/kernel/fork.c
index f2c92c100194..cf535b9d5db7 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1217,24 +1217,8 @@ static int wait_for_vfork_done(struct task_struct *child,
* restoring the old one. . .
* Eric Biederman 10 January 1998
*/
-void mm_release(struct task_struct *tsk, struct mm_struct *mm)
+static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
{
- /* Get rid of any futexes when releasing the mm */
-#ifdef CONFIG_FUTEX
- if (unlikely(tsk->robust_list)) {
- exit_robust_list(tsk);
- tsk->robust_list = NULL;
- }
-#ifdef CONFIG_COMPAT
- if (unlikely(tsk->compat_robust_list)) {
- compat_exit_robust_list(tsk);
- tsk->compat_robust_list = NULL;
- }
-#endif
- if (unlikely(!list_empty(&tsk->pi_state_list)))
- exit_pi_state_list(tsk);
-#endif
-
uprobe_free_utask(tsk);

/* Get rid of any cached register state */
@@ -1267,6 +1251,18 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
complete_vfork_done(tsk);
}

+void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm)
+{
+ futex_exit_release(tsk);
+ mm_release(tsk, mm);
+}
+
+void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm)
+{
+ futex_exec_release(tsk);
+ mm_release(tsk, mm);
+}
+
/*
* Allocate a new mm structure and copy contents from the
* mm structure of the passed in task structure.
@@ -1937,14 +1933,8 @@ static __latent_entropy struct task_struct *copy_process(
#ifdef CONFIG_BLOCK
p->plug = NULL;
#endif
-#ifdef CONFIG_FUTEX
- p->robust_list = NULL;
-#ifdef CONFIG_COMPAT
- p->compat_robust_list = NULL;
-#endif
- INIT_LIST_HEAD(&p->pi_state_list);
- p->pi_state_cache = NULL;
-#endif
+ futex_init_task(p);
+
/*
* sigaltstack should be cleared when sharing the same VM
*/
diff --git a/kernel/futex.c b/kernel/futex.c
index 334dc4cae780..224adcdac6c1 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -341,6 +341,12 @@ static inline bool should_fail_futex(bool fshared)
}
#endif /* CONFIG_FAIL_FUTEX */

+#ifdef CONFIG_COMPAT
+static void compat_exit_robust_list(struct task_struct *curr);
+#else
+static inline void compat_exit_robust_list(struct task_struct *curr) { }
+#endif
+
static inline void futex_get_mm(union futex_key *key)
{
mmgrab(key->private.mm);
@@ -833,6 +839,29 @@ static struct futex_pi_state *alloc_pi_state(void)
return pi_state;
}

+static void pi_state_update_owner(struct futex_pi_state *pi_state,
+ struct task_struct *new_owner)
+{
+ struct task_struct *old_owner = pi_state->owner;
+
+ lockdep_assert_held(&pi_state->pi_mutex.wait_lock);
+
+ if (old_owner) {
+ raw_spin_lock(&old_owner->pi_lock);
+ WARN_ON(list_empty(&pi_state->list));
+ list_del_init(&pi_state->list);
+ raw_spin_unlock(&old_owner->pi_lock);
+ }
+
+ if (new_owner) {
+ raw_spin_lock(&new_owner->pi_lock);
+ WARN_ON(!list_empty(&pi_state->list));
+ list_add(&pi_state->list, &new_owner->pi_state_list);
+ pi_state->owner = new_owner;
+ raw_spin_unlock(&new_owner->pi_lock);
+ }
+}
+
static void get_pi_state(struct futex_pi_state *pi_state)
{
WARN_ON_ONCE(!atomic_inc_not_zero(&pi_state->refcount));
@@ -855,17 +884,11 @@ static void put_pi_state(struct futex_pi_state *pi_state)
* and has cleaned up the pi_state already
*/
if (pi_state->owner) {
- struct task_struct *owner;
unsigned long flags;

raw_spin_lock_irqsave(&pi_state->pi_mutex.wait_lock, flags);
- owner = pi_state->owner;
- if (owner) {
- raw_spin_lock(&owner->pi_lock);
- list_del_init(&pi_state->list);
- raw_spin_unlock(&owner->pi_lock);
- }
- rt_mutex_proxy_unlock(&pi_state->pi_mutex, owner);
+ pi_state_update_owner(pi_state, NULL);
+ rt_mutex_proxy_unlock(&pi_state->pi_mutex);
raw_spin_unlock_irqrestore(&pi_state->pi_mutex.wait_lock, flags);
}

@@ -890,7 +913,7 @@ static void put_pi_state(struct futex_pi_state *pi_state)
* Kernel cleans up PI-state, but userspace is likely hosed.
* (Robust-futex cleanup is separate and might save the day for userspace.)
*/
-void exit_pi_state_list(struct task_struct *curr)
+static void exit_pi_state_list(struct task_struct *curr)
{
struct list_head *next, *head = &curr->pi_state_list;
struct futex_pi_state *pi_state;
@@ -960,7 +983,8 @@ void exit_pi_state_list(struct task_struct *curr)
}
raw_spin_unlock_irq(&curr->pi_lock);
}
-
+#else
+static inline void exit_pi_state_list(struct task_struct *curr) { }
#endif

/*
@@ -1010,7 +1034,8 @@ void exit_pi_state_list(struct task_struct *curr)
* FUTEX_OWNER_DIED bit. See [4]
*
* [10] There is no transient state which leaves owner and user space
- * TID out of sync.
+ * TID out of sync. Except one error case where the kernel is denied
+ * write access to the user address, see fixup_pi_state_owner().
*
*
* Serialization and lifetime rules:
@@ -1169,16 +1194,47 @@ static int attach_to_pi_state(u32 __user *uaddr, u32 uval,
return ret;
}

+/**
+ * wait_for_owner_exiting - Block until the owner has exited
+ * @exiting: Pointer to the exiting task
+ *
+ * Caller must hold a refcount on @exiting.
+ */
+static void wait_for_owner_exiting(int ret, struct task_struct *exiting)
+{
+ if (ret != -EBUSY) {
+ WARN_ON_ONCE(exiting);
+ return;
+ }
+
+ if (WARN_ON_ONCE(ret == -EBUSY && !exiting))
+ return;
+
+ mutex_lock(&exiting->futex_exit_mutex);
+ /*
+ * No point in doing state checking here. If the waiter got here
+ * while the task was in exec()->exec_futex_release() then it can
+ * have any FUTEX_STATE_* value when the waiter has acquired the
+ * mutex. OK, if running, EXITING or DEAD if it reached exit()
+ * already. Highly unlikely and not a problem. Just one more round
+ * through the futex maze.
+ */
+ mutex_unlock(&exiting->futex_exit_mutex);
+
+ put_task_struct(exiting);
+}
+
static int handle_exit_race(u32 __user *uaddr, u32 uval,
struct task_struct *tsk)
{
u32 uval2;

/*
- * If PF_EXITPIDONE is not yet set, then try again.
+ * If the futex exit state is not yet FUTEX_STATE_DEAD, tell the
+ * caller that the alleged owner is busy.
*/
- if (tsk && !(tsk->flags & PF_EXITPIDONE))
- return -EAGAIN;
+ if (tsk && tsk->futex_state != FUTEX_STATE_DEAD)
+ return -EBUSY;

/*
* Reread the user space value to handle the following situation:
@@ -1196,8 +1252,9 @@ static int handle_exit_race(u32 __user *uaddr, u32 uval,
* *uaddr = 0xC0000000; tsk = get_task(PID);
* } if (!tsk->flags & PF_EXITING) {
* ... attach();
- * tsk->flags |= PF_EXITPIDONE; } else {
- * if (!(tsk->flags & PF_EXITPIDONE))
+ * tsk->futex_state = } else {
+ * FUTEX_STATE_DEAD; if (tsk->futex_state !=
+ * FUTEX_STATE_DEAD)
* return -EAGAIN;
* return -ESRCH; <--- FAIL
* }
@@ -1228,7 +1285,8 @@ static int handle_exit_race(u32 __user *uaddr, u32 uval,
* it after doing proper sanity checks.
*/
static int attach_to_pi_owner(u32 __user *uaddr, u32 uval, union futex_key *key,
- struct futex_pi_state **ps)
+ struct futex_pi_state **ps,
+ struct task_struct **exiting)
{
pid_t pid = uval & FUTEX_TID_MASK;
struct futex_pi_state *pi_state;
@@ -1253,22 +1311,33 @@ static int attach_to_pi_owner(u32 __user *uaddr, u32 uval, union futex_key *key,
}

/*
- * We need to look at the task state flags to figure out,
- * whether the task is exiting. To protect against the do_exit
- * change of the task flags, we do this protected by
- * p->pi_lock:
+ * We need to look at the task state to figure out, whether the
+ * task is exiting. To protect against the change of the task state
+ * in futex_exit_release(), we do this protected by p->pi_lock:
*/
raw_spin_lock_irq(&p->pi_lock);
- if (unlikely(p->flags & PF_EXITING)) {
+ if (unlikely(p->futex_state != FUTEX_STATE_OK)) {
/*
- * The task is on the way out. When PF_EXITPIDONE is
- * set, we know that the task has finished the
- * cleanup:
+ * The task is on the way out. When the futex state is
+ * FUTEX_STATE_DEAD, we know that the task has finished
+ * the cleanup:
*/
int ret = handle_exit_race(uaddr, uval, p);

raw_spin_unlock_irq(&p->pi_lock);
- put_task_struct(p);
+ /*
+ * If the owner task is between FUTEX_STATE_EXITING and
+ * FUTEX_STATE_DEAD then store the task pointer and keep
+ * the reference on the task struct. The calling code will
+ * drop all locks, wait for the task to reach
+ * FUTEX_STATE_DEAD and then drop the refcount. This is
+ * required to prevent a live lock when the current task
+ * preempted the exiting task between the two states.
+ */
+ if (ret == -EBUSY)
+ *exiting = p;
+ else
+ put_task_struct(p);
return ret;
}

@@ -1307,7 +1376,8 @@ static int attach_to_pi_owner(u32 __user *uaddr, u32 uval, union futex_key *key,

static int lookup_pi_state(u32 __user *uaddr, u32 uval,
struct futex_hash_bucket *hb,
- union futex_key *key, struct futex_pi_state **ps)
+ union futex_key *key, struct futex_pi_state **ps,
+ struct task_struct **exiting)
{
struct futex_q *top_waiter = futex_top_waiter(hb, key);

@@ -1322,7 +1392,7 @@ static int lookup_pi_state(u32 __user *uaddr, u32 uval,
* We are the first waiter - try to look up the owner based on
* @uval and attach to it.
*/
- return attach_to_pi_owner(uaddr, uval, key, ps);
+ return attach_to_pi_owner(uaddr, uval, key, ps, exiting);
}

static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval)
@@ -1350,6 +1420,8 @@ static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval)
* lookup
* @task: the task to perform the atomic lock work for. This will
* be "current" except in the case of requeue pi.
+ * @exiting: Pointer to store the task pointer of the owner task
+ * which is in the middle of exiting
* @set_waiters: force setting the FUTEX_WAITERS bit (1) or not (0)
*
* Return:
@@ -1358,11 +1430,17 @@ static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval)
* - <0 - error
*
* The hb->lock and futex_key refs shall be held by the caller.
+ *
+ * @exiting is only set when the return value is -EBUSY. If so, this holds
+ * a refcount on the exiting task on return and the caller needs to drop it
+ * after waiting for the exit to complete.
*/
static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
union futex_key *key,
struct futex_pi_state **ps,
- struct task_struct *task, int set_waiters)
+ struct task_struct *task,
+ struct task_struct **exiting,
+ int set_waiters)
{
u32 uval, newval, vpid = task_pid_vnr(task);
struct futex_q *top_waiter;
@@ -1432,7 +1510,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
* attach to the owner. If that fails, no harm done, we only
* set the FUTEX_WAITERS bit in the user space variable.
*/
- return attach_to_pi_owner(uaddr, newval, key, ps);
+ return attach_to_pi_owner(uaddr, newval, key, ps, exiting);
}

/**
@@ -1537,26 +1615,15 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
ret = -EINVAL;
}

- if (ret)
- goto out_unlock;
-
- /*
- * This is a point of no return; once we modify the uval there is no
- * going back and subsequent operations must not fail.
- */
-
- raw_spin_lock(&pi_state->owner->pi_lock);
- WARN_ON(list_empty(&pi_state->list));
- list_del_init(&pi_state->list);
- raw_spin_unlock(&pi_state->owner->pi_lock);
-
- raw_spin_lock(&new_owner->pi_lock);
- WARN_ON(!list_empty(&pi_state->list));
- list_add(&pi_state->list, &new_owner->pi_state_list);
- pi_state->owner = new_owner;
- raw_spin_unlock(&new_owner->pi_lock);
-
- postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
+ if (!ret) {
+ /*
+ * This is a point of no return; once we modified the uval
+ * there is no going back and subsequent operations must
+ * not fail.
+ */
+ pi_state_update_owner(pi_state, new_owner);
+ postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
+ }

out_unlock:
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
@@ -1853,6 +1920,8 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key,
* @key1: the from futex key
* @key2: the to futex key
* @ps: address to store the pi_state pointer
+ * @exiting: Pointer to store the task pointer of the owner task
+ * which is in the middle of exiting
* @set_waiters: force setting the FUTEX_WAITERS bit (1) or not (0)
*
* Try and get the lock on behalf of the top waiter if we can do it atomically.
@@ -1860,16 +1929,20 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key,
* then direct futex_lock_pi_atomic() to force setting the FUTEX_WAITERS bit.
* hb1 and hb2 must be held by the caller.
*
+ * @exiting is only set when the return value is -EBUSY. If so, this holds
+ * a refcount on the exiting task on return and the caller needs to drop it
+ * after waiting for the exit to complete.
+ *
* Return:
* - 0 - failed to acquire the lock atomically;
* - >0 - acquired the lock, return value is vpid of the top_waiter
* - <0 - error
*/
-static int futex_proxy_trylock_atomic(u32 __user *pifutex,
- struct futex_hash_bucket *hb1,
- struct futex_hash_bucket *hb2,
- union futex_key *key1, union futex_key *key2,
- struct futex_pi_state **ps, int set_waiters)
+static int
+futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1,
+ struct futex_hash_bucket *hb2, union futex_key *key1,
+ union futex_key *key2, struct futex_pi_state **ps,
+ struct task_struct **exiting, int set_waiters)
{
struct futex_q *top_waiter = NULL;
u32 curval;
@@ -1906,7 +1979,7 @@ static int futex_proxy_trylock_atomic(u32 __user *pifutex,
*/
vpid = task_pid_vnr(top_waiter->task);
ret = futex_lock_pi_atomic(pifutex, hb2, key2, ps, top_waiter->task,
- set_waiters);
+ exiting, set_waiters);
if (ret == 1) {
requeue_pi_wake_futex(top_waiter, key2, hb2);
return vpid;
@@ -2035,6 +2108,8 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
}

if (requeue_pi && (task_count - nr_wake < nr_requeue)) {
+ struct task_struct *exiting = NULL;
+
/*
* Attempt to acquire uaddr2 and wake the top waiter. If we
* intend to requeue waiters, force setting the FUTEX_WAITERS
@@ -2042,7 +2117,8 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
* faults rather in the requeue loop below.
*/
ret = futex_proxy_trylock_atomic(uaddr2, hb1, hb2, &key1,
- &key2, &pi_state, nr_requeue);
+ &key2, &pi_state,
+ &exiting, nr_requeue);

/*
* At this point the top_waiter has either taken uaddr2 or is
@@ -2069,7 +2145,8 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
* If that call succeeds then we have pi_state and an
* initial refcount on it.
*/
- ret = lookup_pi_state(uaddr2, ret, hb2, &key2, &pi_state);
+ ret = lookup_pi_state(uaddr2, ret, hb2, &key2,
+ &pi_state, &exiting);
}

switch (ret) {
@@ -2087,17 +2164,24 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
if (!ret)
goto retry;
goto out;
+ case -EBUSY:
case -EAGAIN:
/*
* Two reasons for this:
- * - Owner is exiting and we just wait for the
+ * - EBUSY: Owner is exiting and we just wait for the
* exit to complete.
- * - The user space value changed.
+ * - EAGAIN: The user space value changed.
*/
double_unlock_hb(hb1, hb2);
hb_waiters_dec(hb2);
put_futex_key(&key2);
put_futex_key(&key1);
+ /*
+ * Handle the case where the owner is in the middle of
+ * exiting. Wait for the exit to complete otherwise
+ * this task might loop forever, aka. live lock.
+ */
+ wait_for_owner_exiting(ret, exiting);
cond_resched();
goto retry;
default:
@@ -2362,18 +2446,13 @@ static void unqueue_me_pi(struct futex_q *q)
spin_unlock(q->lock_ptr);
}

-static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
- struct task_struct *argowner)
+static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
+ struct task_struct *argowner)
{
+ u32 uval, uninitialized_var(curval), newval, newtid;
struct futex_pi_state *pi_state = q->pi_state;
- u32 uval, uninitialized_var(curval), newval;
struct task_struct *oldowner, *newowner;
- u32 newtid;
- int ret, err = 0;
-
- lockdep_assert_held(q->lock_ptr);
-
- raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+ int err = 0;

oldowner = pi_state->owner;

@@ -2407,14 +2486,12 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
* We raced against a concurrent self; things are
* already fixed up. Nothing to do.
*/
- ret = 0;
- goto out_unlock;
+ return 0;
}

if (__rt_mutex_futex_trylock(&pi_state->pi_mutex)) {
- /* We got the lock after all, nothing to fix. */
- ret = 0;
- goto out_unlock;
+ /* We got the lock. pi_state is correct. Tell caller. */
+ return 1;
}

/*
@@ -2441,8 +2518,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
* We raced against a concurrent self; things are
* already fixed up. Nothing to do.
*/
- ret = 0;
- goto out_unlock;
+ return 1;
}
newowner = argowner;
}
@@ -2472,22 +2548,9 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
* We fixed up user space. Now we need to fix the pi_state
* itself.
*/
- if (pi_state->owner != NULL) {
- raw_spin_lock(&pi_state->owner->pi_lock);
- WARN_ON(list_empty(&pi_state->list));
- list_del_init(&pi_state->list);
- raw_spin_unlock(&pi_state->owner->pi_lock);
- }
+ pi_state_update_owner(pi_state, newowner);

- pi_state->owner = newowner;
-
- raw_spin_lock(&newowner->pi_lock);
- WARN_ON(!list_empty(&pi_state->list));
- list_add(&pi_state->list, &newowner->pi_state_list);
- raw_spin_unlock(&newowner->pi_lock);
- raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
-
- return 0;
+ return argowner == current;

/*
* In order to reschedule or handle a page fault, we need to drop the
@@ -2508,17 +2571,16 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,

switch (err) {
case -EFAULT:
- ret = fault_in_user_writeable(uaddr);
+ err = fault_in_user_writeable(uaddr);
break;

case -EAGAIN:
cond_resched();
- ret = 0;
+ err = 0;
break;

default:
WARN_ON_ONCE(1);
- ret = err;
break;
}

@@ -2528,17 +2590,44 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
/*
* Check if someone else fixed it for us:
*/
- if (pi_state->owner != oldowner) {
- ret = 0;
- goto out_unlock;
- }
+ if (pi_state->owner != oldowner)
+ return argowner == current;

- if (ret)
- goto out_unlock;
+ /* Retry if err was -EAGAIN or the fault in succeeded */
+ if (!err)
+ goto retry;

- goto retry;
+ /*
+ * fault_in_user_writeable() failed so user state is immutable. At
+ * best we can make the kernel state consistent but user state will
+ * be most likely hosed and any subsequent unlock operation will be
+ * rejected due to PI futex rule [10].
+ *
+ * Ensure that the rtmutex owner is also the pi_state owner despite
+ * the user space value claiming something different. There is no
+ * point in unlocking the rtmutex if current is the owner as it
+ * would need to wait until the next waiter has taken the rtmutex
+ * to guarantee consistent state. Keep it simple. Userspace asked
+ * for this wreckaged state.
+ *
+ * The rtmutex has an owner - either current or some other
+ * task. See the EAGAIN loop above.
+ */
+ pi_state_update_owner(pi_state, rt_mutex_owner(&pi_state->pi_mutex));

-out_unlock:
+ return err;
+}
+
+static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
+ struct task_struct *argowner)
+{
+ struct futex_pi_state *pi_state = q->pi_state;
+ int ret;
+
+ lockdep_assert_held(q->lock_ptr);
+
+ raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+ ret = __fixup_pi_state_owner(uaddr, q, argowner);
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
return ret;
}
@@ -2562,8 +2651,6 @@ static long futex_wait_restart(struct restart_block *restart);
*/
static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
{
- int ret = 0;
-
if (locked) {
/*
* Got the lock. We might not be the anticipated owner if we
@@ -2574,8 +2661,8 @@ static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
* stable state, anything else needs more attention.
*/
if (q->pi_state->owner != current)
- ret = fixup_pi_state_owner(uaddr, q, current);
- goto out;
+ return fixup_pi_state_owner(uaddr, q, current);
+ return 1;
}

/*
@@ -2586,24 +2673,17 @@ static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
* Another speculative read; pi_state->owner == current is unstable
* but needs our attention.
*/
- if (q->pi_state->owner == current) {
- ret = fixup_pi_state_owner(uaddr, q, NULL);
- goto out;
- }
+ if (q->pi_state->owner == current)
+ return fixup_pi_state_owner(uaddr, q, NULL);

/*
* Paranoia check. If we did not take the lock, then we should not be
- * the owner of the rt_mutex.
+ * the owner of the rt_mutex. Warn and establish consistent state.
*/
- if (rt_mutex_owner(&q->pi_state->pi_mutex) == current) {
- printk(KERN_ERR "fixup_owner: ret = %d pi-mutex: %p "
- "pi-state %p\n", ret,
- q->pi_state->pi_mutex.owner,
- q->pi_state->owner);
- }
+ if (WARN_ON_ONCE(rt_mutex_owner(&q->pi_state->pi_mutex) == current))
+ return fixup_pi_state_owner(uaddr, q, current);

-out:
- return ret ? ret : locked;
+ return 0;
}

/**
@@ -2824,7 +2904,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
ktime_t *time, int trylock)
{
struct hrtimer_sleeper timeout, *to = NULL;
- struct futex_pi_state *pi_state = NULL;
+ struct task_struct *exiting = NULL;
struct rt_mutex_waiter rt_waiter;
struct futex_hash_bucket *hb;
struct futex_q q = futex_q_init;
@@ -2852,7 +2932,8 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
retry_private:
hb = queue_lock(&q);

- ret = futex_lock_pi_atomic(uaddr, hb, &q.key, &q.pi_state, current, 0);
+ ret = futex_lock_pi_atomic(uaddr, hb, &q.key, &q.pi_state, current,
+ &exiting, 0);
if (unlikely(ret)) {
/*
* Atomic work succeeded and we got the lock,
@@ -2865,15 +2946,22 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
goto out_unlock_put_key;
case -EFAULT:
goto uaddr_faulted;
+ case -EBUSY:
case -EAGAIN:
/*
* Two reasons for this:
- * - Task is exiting and we just wait for the
+ * - EBUSY: Task is exiting and we just wait for the
* exit to complete.
- * - The user space value changed.
+ * - EAGAIN: The user space value changed.
*/
queue_unlock(hb);
put_futex_key(&q.key);
+ /*
+ * Handle the case where the owner is in the middle of
+ * exiting. Wait for the exit to complete otherwise
+ * this task might loop forever, aka. live lock.
+ */
+ wait_for_owner_exiting(ret, exiting);
cond_resched();
goto retry;
default:
@@ -2958,23 +3046,9 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
if (res)
ret = (res < 0) ? res : 0;

- /*
- * If fixup_owner() faulted and was unable to handle the fault, unlock
- * it and return the fault to userspace.
- */
- if (ret && (rt_mutex_owner(&q.pi_state->pi_mutex) == current)) {
- pi_state = q.pi_state;
- get_pi_state(pi_state);
- }
-
/* Unqueue and drop the lock */
unqueue_me_pi(&q);

- if (pi_state) {
- rt_mutex_futex_unlock(&pi_state->pi_mutex);
- put_pi_state(pi_state);
- }
-
goto out_put_key;

out_unlock_put_key:
@@ -3240,7 +3314,6 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
u32 __user *uaddr2)
{
struct hrtimer_sleeper timeout, *to = NULL;
- struct futex_pi_state *pi_state = NULL;
struct rt_mutex_waiter rt_waiter;
struct futex_hash_bucket *hb;
union futex_key key2 = FUTEX_KEY_INIT;
@@ -3325,16 +3398,17 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
if (q.pi_state && (q.pi_state->owner != current)) {
spin_lock(q.lock_ptr);
ret = fixup_pi_state_owner(uaddr2, &q, current);
- if (ret && rt_mutex_owner(&q.pi_state->pi_mutex) == current) {
- pi_state = q.pi_state;
- get_pi_state(pi_state);
- }
/*
* Drop the reference to the pi state which
* the requeue_pi() code acquired for us.
*/
put_pi_state(q.pi_state);
spin_unlock(q.lock_ptr);
+ /*
+ * Adjust the return value. It's either -EFAULT or
+ * success (1) but the caller expects 0 for success.
+ */
+ ret = ret < 0 ? ret : 0;
}
} else {
struct rt_mutex *pi_mutex;
@@ -3365,25 +3439,10 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
if (res)
ret = (res < 0) ? res : 0;

- /*
- * If fixup_pi_state_owner() faulted and was unable to handle
- * the fault, unlock the rt_mutex and return the fault to
- * userspace.
- */
- if (ret && rt_mutex_owner(&q.pi_state->pi_mutex) == current) {
- pi_state = q.pi_state;
- get_pi_state(pi_state);
- }
-
/* Unqueue and drop the lock. */
unqueue_me_pi(&q);
}

- if (pi_state) {
- rt_mutex_futex_unlock(&pi_state->pi_mutex);
- put_pi_state(pi_state);
- }
-
if (ret == -EINTR) {
/*
* We've already been requeued, but cannot restart by calling
@@ -3625,7 +3684,7 @@ static inline int fetch_robust_entry(struct robust_list __user **entry,
*
* We silently return on any sign of list-walking problem.
*/
-void exit_robust_list(struct task_struct *curr)
+static void exit_robust_list(struct task_struct *curr)
{
struct robust_list_head __user *head = curr->robust_list;
struct robust_list __user *entry, *next_entry, *pending;
@@ -3690,6 +3749,114 @@ void exit_robust_list(struct task_struct *curr)
}
}

+static void futex_cleanup(struct task_struct *tsk)
+{
+ if (unlikely(tsk->robust_list)) {
+ exit_robust_list(tsk);
+ tsk->robust_list = NULL;
+ }
+
+#ifdef CONFIG_COMPAT
+ if (unlikely(tsk->compat_robust_list)) {
+ compat_exit_robust_list(tsk);
+ tsk->compat_robust_list = NULL;
+ }
+#endif
+
+ if (unlikely(!list_empty(&tsk->pi_state_list)))
+ exit_pi_state_list(tsk);
+}
+
+/**
+ * futex_exit_recursive - Set the tasks futex state to FUTEX_STATE_DEAD
+ * @tsk: task to set the state on
+ *
+ * Set the futex exit state of the task lockless. The futex waiter code
+ * observes that state when a task is exiting and loops until the task has
+ * actually finished the futex cleanup. The worst case for this is that the
+ * waiter runs through the wait loop until the state becomes visible.
+ *
+ * This is called from the recursive fault handling path in do_exit().
+ *
+ * This is best effort. Either the futex exit code has run already or
+ * not. If the OWNER_DIED bit has been set on the futex then the waiter can
+ * take it over. If not, the problem is pushed back to user space. If the
+ * futex exit code did not run yet, then an already queued waiter might
+ * block forever, but there is nothing which can be done about that.
+ */
+void futex_exit_recursive(struct task_struct *tsk)
+{
+ /* If the state is FUTEX_STATE_EXITING then futex_exit_mutex is held */
+ if (tsk->futex_state == FUTEX_STATE_EXITING)
+ mutex_unlock(&tsk->futex_exit_mutex);
+ tsk->futex_state = FUTEX_STATE_DEAD;
+}
+
+static void futex_cleanup_begin(struct task_struct *tsk)
+{
+ /*
+ * Prevent various race issues against a concurrent incoming waiter
+ * including live locks by forcing the waiter to block on
+ * tsk->futex_exit_mutex when it observes FUTEX_STATE_EXITING in
+ * attach_to_pi_owner().
+ */
+ mutex_lock(&tsk->futex_exit_mutex);
+
+ /*
+ * Switch the state to FUTEX_STATE_EXITING under tsk->pi_lock.
+ *
+ * This ensures that all subsequent checks of tsk->futex_state in
+ * attach_to_pi_owner() must observe FUTEX_STATE_EXITING with
+ * tsk->pi_lock held.
+ *
+ * It guarantees also that a pi_state which was queued right before
+ * the state change under tsk->pi_lock by a concurrent waiter must
+ * be observed in exit_pi_state_list().
+ */
+ raw_spin_lock_irq(&tsk->pi_lock);
+ tsk->futex_state = FUTEX_STATE_EXITING;
+ raw_spin_unlock_irq(&tsk->pi_lock);
+}
+
+static void futex_cleanup_end(struct task_struct *tsk, int state)
+{
+ /*
+ * Lockless store. The only side effect is that an observer might
+ * take another loop until it becomes visible.
+ */
+ tsk->futex_state = state;
+ /*
+ * Drop the exit protection. This unblocks waiters which observed
+ * FUTEX_STATE_EXITING to reevaluate the state.
+ */
+ mutex_unlock(&tsk->futex_exit_mutex);
+}
+
+void futex_exec_release(struct task_struct *tsk)
+{
+ /*
+ * The state handling is done for consistency, but in the case of
+ * exec() there is no way to prevent futher damage as the PID stays
+ * the same. But for the unlikely and arguably buggy case that a
+ * futex is held on exec(), this provides at least as much state
+ * consistency protection which is possible.
+ */
+ futex_cleanup_begin(tsk);
+ futex_cleanup(tsk);
+ /*
+ * Reset the state to FUTEX_STATE_OK. The task is alive and about
+ * exec a new binary.
+ */
+ futex_cleanup_end(tsk, FUTEX_STATE_OK);
+}
+
+void futex_exit_release(struct task_struct *tsk)
+{
+ futex_cleanup_begin(tsk);
+ futex_cleanup(tsk);
+ futex_cleanup_end(tsk, FUTEX_STATE_DEAD);
+}
+
long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
u32 __user *uaddr2, u32 val2, u32 val3)
{
@@ -3817,7 +3984,7 @@ static void __user *futex_uaddr(struct robust_list __user *entry,
*
* We silently return on any sign of list-walking problem.
*/
-void compat_exit_robust_list(struct task_struct *curr)
+static void compat_exit_robust_list(struct task_struct *curr)
{
struct compat_robust_list_head __user *head = curr->compat_robust_list;
struct robust_list __user *entry, *next_entry, *pending;
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 9562aaa2afdc..a5ec4f68527e 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1719,8 +1719,7 @@ void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
* possible because it belongs to the pi_state which is about to be freed
* and it is not longer visible to other tasks.
*/
-void rt_mutex_proxy_unlock(struct rt_mutex *lock,
- struct task_struct *proxy_owner)
+void rt_mutex_proxy_unlock(struct rt_mutex *lock)
{
debug_rt_mutex_proxy_unlock(lock);
rt_mutex_set_owner(lock, NULL);
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index d1d62f942be2..ca6fb489007b 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -133,8 +133,7 @@ enum rtmutex_chainwalk {
extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner);
-extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
- struct task_struct *proxy_owner);
+extern void rt_mutex_proxy_unlock(struct rt_mutex *lock);
extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter,
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 87ce9736043d..360129e47540 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -4393,6 +4393,8 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)

if (!cpumask_test_cpu(cpu, buffer->cpumask))
return;
+ /* prevent another thread from changing buffer sizes */
+ mutex_lock(&buffer->mutex);

atomic_inc(&buffer->resize_disabled);
atomic_inc(&cpu_buffer->record_disabled);
@@ -4416,6 +4418,8 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)

atomic_dec(&cpu_buffer->record_disabled);
atomic_dec(&buffer->resize_disabled);
+
+ mutex_unlock(&buffer->mutex);
}
EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu);

diff --git a/mm/slub.c b/mm/slub.c
index 02295fa61583..eac80b0516fe 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5766,10 +5766,8 @@ static int sysfs_slab_add(struct kmem_cache *s)

s->kobj.kset = kset;
err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
- if (err) {
- kobject_put(&s->kobj);
+ if (err)
goto out;
- }

err = sysfs_create_group(&s->kobj, &slab_attr_group);
if (err)
diff --git a/tools/build/Makefile b/tools/build/Makefile
index 727050c40f09..8a55378e8b7c 100644
--- a/tools/build/Makefile
+++ b/tools/build/Makefile
@@ -15,10 +15,6 @@ endef
$(call allow-override,CC,$(CROSS_COMPILE)gcc)
$(call allow-override,LD,$(CROSS_COMPILE)ld)

-HOSTCC ?= gcc
-HOSTLD ?= ld
-HOSTAR ?= ar
-
export HOSTCC HOSTLD HOSTAR

ifeq ($(V),1)
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index baa92279c137..15f32f67cf34 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -7,15 +7,6 @@ ARCH := x86
endif

# always use the host compiler
-ifneq ($(LLVM),)
-HOSTAR ?= llvm-ar
-HOSTCC ?= clang
-HOSTLD ?= ld.lld
-else
-HOSTAR ?= ar
-HOSTCC ?= gcc
-HOSTLD ?= ld
-endif
AR = $(HOSTAR)
CC = $(HOSTCC)
LD = $(HOSTLD)
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 0be411695379..678aa7feb84d 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -148,10 +148,6 @@ endef

LD += $(EXTRA_LDFLAGS)

-HOSTCC ?= gcc
-HOSTLD ?= ld
-HOSTAR ?= ar
-
PKG_CONFIG = $(CROSS_COMPILE)pkg-config
LLVM_CONFIG ?= llvm-config

diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
index fc116c060b98..32ff7baf39df 100644
--- a/tools/power/acpi/Makefile.config
+++ b/tools/power/acpi/Makefile.config
@@ -57,7 +57,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
CROSS_COMPILE ?= $(CROSS)
LD = $(CC)
-HOSTCC = gcc

# check if compiler option is supported
cc-supports = ${shell if $(CC) ${1} -S -o /dev/null -x c /dev/null > /dev/null 2>&1; then echo "$(1)"; fi;}
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 8fc6b1ca47dc..42dbe05b1807 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -60,6 +60,16 @@ $(call allow-override,LD,$(CROSS_COMPILE)ld)
$(call allow-override,CXX,$(CROSS_COMPILE)g++)
$(call allow-override,STRIP,$(CROSS_COMPILE)strip)

+ifneq ($(LLVM),)
+HOSTAR ?= llvm-ar
+HOSTCC ?= clang
+HOSTLD ?= ld.lld
+else
+HOSTAR ?= ar
+HOSTCC ?= gcc
+HOSTLD ?= ld
+endif
+
ifeq ($(CC_NO_CLANG), 1)
EXTRA_WARNINGS += -Wstrict-aliasing=3
endif
\
 
 \ /
  Last update: 2021-01-30 15:16    [W:0.067 / U:3.644 seconds]
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