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Hi, We have a few users experiencing locking problem. When starting Thunderbird, there is no new emails in Inbox. Dovecot createa a lock file /var/spool/mail/<user>.lock. It never completes openning Inbox. If closing the mail client, the open imap session does not get closed, nor the lock file get deleted. Here are the errors in log: dovecot: Oct 13 11:18:35 Warning: IMAP(user1): Our

...ther node to the join, then we * need to back off temporarily and let them * complete. */ #define DLM_JOIN_TIMEOUT_MSECS 90000 if (status == -EAGAIN) { if (signal_pending(current)) { status = -ERESTARTSYS; goto bail; } if (total_backoff > msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) { status = -ERESTARTSYS; mlog(ML_NOTICE, "...

...mp;rng_mutex); + udelay(100); if (need_resched()) schedule_timeout_interruptible(1); @@ -233,10 +234,10 @@ static ssize_t hwrng_attr_current_store(struct device *dev, int err; struct hwrng *rng; + err = -ENODEV; err = mutex_lock_interruptible(&rng_mutex); if (err) return -ERESTARTSYS; - err = -ENODEV; list_for_each_entry(rng, &rng_list, list) { if (strcmp(rng->name, buf) == 0) { if (rng == current_rng) { @@ -270,8 +271,8 @@ static ssize_t hwrng_attr_current_show(struct device *dev, return -ERESTARTSYS; if (current_rng) name = current_rng->name; - ret...

...mp;rng_mutex); + udelay(100); if (need_resched()) schedule_timeout_interruptible(1); @@ -233,10 +234,10 @@ static ssize_t hwrng_attr_current_store(struct device *dev, int err; struct hwrng *rng; + err = -ENODEV; err = mutex_lock_interruptible(&rng_mutex); if (err) return -ERESTARTSYS; - err = -ENODEV; list_for_each_entry(rng, &rng_list, list) { if (strcmp(rng->name, buf) == 0) { if (rng == current_rng) { @@ -270,8 +271,8 @@ static ssize_t hwrng_attr_current_show(struct device *dev, return -ERESTARTSYS; if (current_rng) name = current_rng->name; - ret...

...ic ssize_t hwrng_attr_current_store(struct device *dev, > int err; > struct hwrng *rng; The following hunk doesn't work: > + err = -ENODEV; > err = mutex_lock_interruptible(&rng_mutex); err is being set to another value in the next line! > if (err) > return -ERESTARTSYS; > - err = -ENODEV; And all usage of err below now won't have -ENODEV but some other value. > list_for_each_entry(rng, &rng_list, list) { > if (strcmp(rng->name, buf) == 0) { > if (rng == current_rng) { > @@ -270,8 +271,8 @@ static ssize_t hwrng_attr_current_sho...

...ic ssize_t hwrng_attr_current_store(struct device *dev, > int err; > struct hwrng *rng; The following hunk doesn't work: > + err = -ENODEV; > err = mutex_lock_interruptible(&rng_mutex); err is being set to another value in the next line! > if (err) > return -ERESTARTSYS; > - err = -ENODEV; And all usage of err below now won't have -ENODEV but some other value. > list_for_each_entry(rng, &rng_list, list) { > if (strcmp(rng->name, buf) == 0) { > if (rng == current_rng) { > @@ -270,8 +271,8 @@ static ssize_t hwrng_attr_current_sho...

.../virtio/virtgpu_drv.h @@ -402,9 +402,9 @@ static inline int virtio_gpu_object_reserve(struct virtio_gpu_object *bo) { int r; - r = ttm_bo_reserve(&bo->tbo, true, false, NULL); + r = reservation_object_lock_interruptible(bo->gem_base.resv, NULL); if (unlikely(r != 0)) { - if (r != -ERESTARTSYS) { + if (r != -ERESTARTSYS && r != -EINTR) { struct virtio_gpu_device *qdev = bo->gem_base.dev->dev_private; dev_err(qdev->dev, "%p reserve failed\n", bo); @@ -416,7 +416,7 @@ static inline int virtio_gpu_object_reserve(struct virtio_gpu_object *bo) stati...

If we read hwrng by long-running dd process, it takes too much cpu time. When we check hwrng attributes from sysfs by cat, it gets stuck. The problem can only be reproduced with non-smp guest with slow backend. This patchset changed hwrng core to always delay 10 jiffies, cat process have chance to execute protected code, the problem is resolved. Thanks. Amos Kong (2): virtio-rng cleanup: move

If we read hwrng by long-running dd process, it takes too much cpu time. When we check hwrng attributes from sysfs by cat, it gets stuck. The problem can only be reproduced with non-smp guest with slow backend. This patchset changed hwrng core to always delay 10 jiffies, cat process have chance to execute protected code, the problem is resolved. Thanks. Amos Kong (2): virtio-rng cleanup: move

...om a smb filesystem over a wireless link. I guess there was some error > on the wireless link, which in turn caused an error condition for the > smb filesystem. > > In the log, smb_file_read reports error=4294966784 (0xfffffe00), which > also shows up in the slab dumps, and also is -ERESTARTSYS. Error code > 27499 corresponds to 0x6b6b, so the rq_errno field seems to be the only > one being set after freeing the slab. > > In smb_add_request (which is the only place in smbfs where I found > ERESTARTSYS), I found the following: > > if (!timeleft || signal_pend...

If we read hwrng by long-running dd process, it takes too much cpu time and almost hold the mutex lock. When we check hwrng attributes from sysfs by cat, it gets stuck in waiting the lock releaseing. The problem can only be reproduced with non-smp guest with slow backend. This patchset resolves the issue by changing rng_dev_read() to always schedule 10 jiffies after release mutex lock, then cat

If we read hwrng by long-running dd process, it takes too much cpu time and almost hold the mutex lock. When we check hwrng attributes from sysfs by cat, it gets stuck in waiting the lock releaseing. The problem can only be reproduced with non-smp guest with slow backend. This patchset resolves the issue by changing rng_dev_read() to always schedule 10 jiffies after release mutex lock, then cat

...; > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c > index aa30a25..c591d7e 100644 > --- a/drivers/char/hw_random/core.c > +++ b/drivers/char/hw_random/core.c > @@ -270,8 +270,8 @@ static ssize_t hwrng_attr_current_show(struct device *dev, > return -ERESTARTSYS; > if (current_rng) > name = current_rng->name; > - ret = snprintf(buf, PAGE_SIZE, "%s\n", name); > mutex_unlock(&rng_mutex); > + ret = snprintf(buf, PAGE_SIZE, "%s\n", name); I'm not sure this is safe. Name is just a pointer. What if the hwrng...

...; > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c > index aa30a25..c591d7e 100644 > --- a/drivers/char/hw_random/core.c > +++ b/drivers/char/hw_random/core.c > @@ -270,8 +270,8 @@ static ssize_t hwrng_attr_current_show(struct device *dev, > return -ERESTARTSYS; > if (current_rng) > name = current_rng->name; > - ret = snprintf(buf, PAGE_SIZE, "%s\n", name); > mutex_unlock(&rng_mutex); > + ret = snprintf(buf, PAGE_SIZE, "%s\n", name); I'm not sure this is safe. Name is just a pointer. What if the hwrng...

...filp, char __user *buf, mutex_unlock(&rng_mutex); - if (need_resched()) - schedule_timeout_interruptible(1); + schedule_timeout_interruptible(1); if (signal_pending(current)) { err = -ERESTARTSYS; > > schedule_timeout_interruptible(1); > > @@ -233,10 +234,10 @@ static ssize_t hwrng_attr_current_store(struct device *dev, > > int err; > > struct hwrng *rng; > The following hunk doesn't work: > > > + err = -ENODEV; > > err = mutex_loc...

...mp;rng_mutex); + udelay(100); if (need_resched()) schedule_timeout_interruptible(1); @@ -233,10 +234,10 @@ static ssize_t hwrng_attr_current_store(struct device *dev, int err; struct hwrng *rng; + err = -ENODEV; err = mutex_lock_interruptible(&rng_mutex); if (err) return -ERESTARTSYS; - err = -ENODEV; list_for_each_entry(rng, &rng_list, list) { if (strcmp(rng->name, buf) == 0) { if (rng == current_rng) { @@ -270,8 +271,8 @@ static ssize_t hwrng_attr_current_show(struct device *dev, return -ERESTARTSYS; if (current_rng) name = current_rng->name; - ret...

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My original was pain, Rusty posted a real fix. This patchset fixed two issue in v1, and tested by my 6+ cases. | test 0: | hotunplug rng device from qemu monitor | | test 1: | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 2: |

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My original was pain, Rusty posted a real fix. This patchset fixed two issue in v1, and tested by my 6+ cases. | test 0: | hotunplug rng device from qemu monitor | | test 1: | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 2: |

...+ if (!current_rng) + return; + + kref_put(&current_rng->ref, cleanup_rng); + current_rng = NULL; +} + +/* Returns ERR_PTR(), NULL or refcounted hwrng */ +static struct hwrng *get_current_rng(void) +{ + struct hwrng *rng; + + if (mutex_lock_interruptible(&rng_mutex)) + return ERR_PTR(-ERESTARTSYS); + + rng = current_rng; + if (rng) + kref_get(&rng->ref); + + mutex_unlock(&rng_mutex); + return rng; +} + +static void put_rng(struct hwrng *rng) +{ + /* + * Hold rng_mutex here so we serialize in case they set_current_rng + * on rng again immediately. + */ + mutex_lock(&rng_mu...

...+ if (!current_rng) + return; + + kref_put(&current_rng->ref, cleanup_rng); + current_rng = NULL; +} + +/* Returns ERR_PTR(), NULL or refcounted hwrng */ +static struct hwrng *get_current_rng(void) +{ + struct hwrng *rng; + + if (mutex_lock_interruptible(&rng_mutex)) + return ERR_PTR(-ERESTARTSYS); + + rng = current_rng; + if (rng) + kref_get(&rng->ref); + + mutex_unlock(&rng_mutex); + return rng; +} + +static void put_rng(struct hwrng *rng) +{ + /* + * Hold rng_mutex here so we serialize in case they set_current_rng + * on rng again immediately. + */ + mutex_lock(&rng_mu...