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a8fabb3852
In case a user process using xenbus has open transactions and is killed
e.g. via ctrl-C the following cleanup of the allocated resources might
result in a deadlock due to trying to end a transaction in the xenbus
worker thread:
[ 2551.474706] INFO: task xenbus:37 blocked for more than 120 seconds.
[ 2551.492215] Tainted: P OE 5.0.0-29-generic #5
[ 2551.510263] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 2551.528585] xenbus D 0 37 2 0x80000080
[ 2551.528590] Call Trace:
[ 2551.528603] __schedule+0x2c0/0x870
[ 2551.528606] ? _cond_resched+0x19/0x40
[ 2551.528632] schedule+0x2c/0x70
[ 2551.528637] xs_talkv+0x1ec/0x2b0
[ 2551.528642] ? wait_woken+0x80/0x80
[ 2551.528645] xs_single+0x53/0x80
[ 2551.528648] xenbus_transaction_end+0x3b/0x70
[ 2551.528651] xenbus_file_free+0x5a/0x160
[ 2551.528654] xenbus_dev_queue_reply+0xc4/0x220
[ 2551.528657] xenbus_thread+0x7de/0x880
[ 2551.528660] ? wait_woken+0x80/0x80
[ 2551.528665] kthread+0x121/0x140
[ 2551.528667] ? xb_read+0x1d0/0x1d0
[ 2551.528670] ? kthread_park+0x90/0x90
[ 2551.528673] ret_from_fork+0x35/0x40
Fix this by doing the cleanup via a workqueue instead.
Reported-by: James Dingwall <james@dingwall.me.uk>
Fixes:
|
||
---|---|---|
.. | ||
events | ||
xen-pciback | ||
xenbus | ||
xenfs | ||
acpi.c | ||
arm-device.c | ||
balloon.c | ||
biomerge.c | ||
cpu_hotplug.c | ||
dbgp.c | ||
efi.c | ||
evtchn.c | ||
features.c | ||
gntalloc.c | ||
gntdev-common.h | ||
gntdev-dmabuf.c | ||
gntdev-dmabuf.h | ||
gntdev.c | ||
grant-table.c | ||
Kconfig | ||
Makefile | ||
manage.c | ||
mcelog.c | ||
mem-reservation.c | ||
pci.c | ||
pcpu.c | ||
platform-pci.c | ||
preempt.c | ||
privcmd-buf.c | ||
privcmd.c | ||
privcmd.h | ||
pvcalls-back.c | ||
pvcalls-front.c | ||
pvcalls-front.h | ||
swiotlb-xen.c | ||
sys-hypervisor.c | ||
time.c | ||
xen-acpi-cpuhotplug.c | ||
xen-acpi-memhotplug.c | ||
xen-acpi-pad.c | ||
xen-acpi-processor.c | ||
xen-balloon.c | ||
xen-front-pgdir-shbuf.c | ||
xen-scsiback.c | ||
xen-stub.c | ||
xlate_mmu.c |