search for: cleanup_don

From: Rusty Russell <rusty at rustcorp.com.au> The previous patch added one potential problem: we can still be reading from a hwrng when it's unregistered. Add a wait for zero in the hwrng_unregister path. v4: add cleanup_done flag to insure that cleanup is done Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> Signed-off-by: Amos Kong <akong at redhat.com> --- drivers/char/hw_random/core.c | 8 ++++++++ include/linux/hw_random.h | 1 + 2 files changed, 9 insertions(+) diff --git a/drivers/char/...

From: Rusty Russell <rusty at rustcorp.com.au> The previous patch added one potential problem: we can still be reading from a hwrng when it's unregistered. Add a wait for zero in the hwrng_unregister path. v4: add cleanup_done flag to insure that cleanup is done Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> Signed-off-by: Amos Kong <akong at redhat.com> --- drivers/char/hw_random/core.c | 8 ++++++++ include/linux/hw_random.h | 1 + 2 files changed, 9 insertions(+) diff --git a/drivers/char/...

...ong <akong at redhat.com> writes: > From: Rusty Russell <rusty at rustcorp.com.au> > > The previous patch added one potential problem: we can still be > reading from a hwrng when it's unregistered. Add a wait for zero > in the hwrng_unregister path. > > v4: add cleanup_done flag to insure that cleanup is done That's a bit weird. The usual pattern would be to hold a reference until we're actually finished, but this reference is a bit weird. We hold the mutex across cleanup, so we could grab that but we have to take care sleeping inside wait_event, otherwise...

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My hotplug tests: | 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: | guest) # dd if=/dev/random of=/dev/null & | hotunplug rng device from qemu monitor | | test

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My hotplug tests: | 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: | guest) # dd if=/dev/random of=/dev/null & | hotunplug rng device from qemu monitor | | test

...sc/hw_random/rng_* | | test 5: | guest) # dd if=/dev/hwrng of=/dev/null | cancel dd process after 10 seconds | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 6: | use a fifo as rng backend, execute test 0 ~ 5 with no input of fifo V5: reset cleanup_done flag, drop redundant init of reference count, use compiler barrier to prevent recording. V4: update patch 4 to fix corrupt, decrease last reference for triggering the cleanup, fix unregister race pointed by Herbert V3: initialize kref to 1 V2: added patch 2 to fix a deadlock, update curren...

...sc/hw_random/rng_* | | test 5: | guest) # dd if=/dev/hwrng of=/dev/null | cancel dd process after 10 seconds | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 6: | use a fifo as rng backend, execute test 0 ~ 5 with no input of fifo V5: reset cleanup_done flag, drop redundant init of reference count, use compiler barrier to prevent recording. V4: update patch 4 to fix corrupt, decrease last reference for triggering the cleanup, fix unregister race pointed by Herbert V3: initialize kref to 1 V2: added patch 2 to fix a deadlock, update curren...

...sc/hw_random/rng_* | | test 5: | guest) # dd if=/dev/hwrng of=/dev/null | cancel dd process after 10 seconds | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 6: | use a fifo as rng backend, execute test 0 ~ 5 with no input of fifo V5: reset cleanup_done flag, drop redundant init of reference count, use compiler barrier to prevent recording. V4: update patch 4 to fix corrupt, decrease last reference for triggering the cleanup, fix unregister race pointed by Herbert V3: initialize kref to 1 V2: added patch 2 to fix a deadlock, update curren...

...sc/hw_random/rng_* | | test 5: | guest) # dd if=/dev/hwrng of=/dev/null | cancel dd process after 10 seconds | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 6: | use a fifo as rng backend, execute test 0 ~ 5 with no input of fifo V5: reset cleanup_done flag, drop redundant init of reference count, use compiler barrier to prevent recording. V4: update patch 4 to fix corrupt, decrease last reference for triggering the cleanup, fix unregister race pointed by Herbert V3: initialize kref to 1 V2: added patch 2 to fix a deadlock, update curren...

On Thu, Sep 18, 2014 at 12:18:24PM +0930, Rusty Russell wrote: > The previous patch added one potential problem: we can still be > reading from a hwrng when it's unregistered. Add a wait for zero > in the hwrng_unregister path. > > Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> > --- > drivers/char/hw_random/core.c | 5 +++++ > 1 file changed, 5

On Thu, Sep 18, 2014 at 12:18:24PM +0930, Rusty Russell wrote: > The previous patch added one potential problem: we can still be > reading from a hwrng when it's unregistered. Add a wait for zero > in the hwrng_unregister path. > > Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> > --- > drivers/char/hw_random/core.c | 5 +++++ > 1 file changed, 5

On Mon, Nov 03, 2014 at 11:56:24PM +0800, Amos Kong wrote: > > @@ -98,6 +99,8 @@ static inline void cleanup_rng(struct kref *kref) > > if (rng->cleanup) > rng->cleanup(rng); You need a compiler barrier here to prevent reordering. > + rng->cleanup_done = true; Thanks, -- Email: Herbert Xu <herbert at gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt