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