linux/drivers/xen
Juergen Gross a8fabb3852 xen/xenbus: fix self-deadlock after killing user process
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: fd8aa9095a ("xen: optimize xenbus driver for multiple concurrent xenstore accesses")
Cc: <stable@vger.kernel.org> # 4.11
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2019-10-02 16:40:11 -04:00
..
events xen/events: fix binding user event channels to cpus 2019-07-17 08:09:57 +02:00
xen-pciback xen/pciback: remove set but not used variable 'old_state' 2019-07-26 10:29:05 +02:00
xenbus xen/xenbus: fix self-deadlock after killing user process 2019-10-02 16:40:11 -04:00
xenfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
acpi.c
arm-device.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
balloon.c xen/balloon: Clear PG_offline in balloon_retrieve() 2019-10-01 15:52:53 -04:00
biomerge.c block: pass page to xen_biovec_phys_mergeable 2019-04-01 12:11:13 -06:00
cpu_hotplug.c xen, cpu_hotplug: Prevent an out of bounds access 2019-03-08 17:58:14 +01:00
dbgp.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
efi.c xen/efi: have a common runtime setup function 2019-10-02 10:31:07 -04:00
evtchn.c xen/events: fix binding user event channels to cpus 2019-07-17 08:09:57 +02:00
features.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
gntalloc.c
gntdev-common.h xen/gntdev: Add initial support for dma-buf UAPI 2018-07-26 23:05:14 -04:00
gntdev-dmabuf.c xen/gntdev: Check and release imported dma-bufs on close 2019-02-18 06:50:10 +01:00
gntdev-dmabuf.h xen/gntdev: Do not destroy context while dma-bufs are in use 2019-02-18 06:50:03 +01:00
gntdev.c xen/gntdev.c: Replace vm_map_pages() with vm_map_pages_zero() 2019-07-31 08:13:59 +02:00
grant-table.c xen: fixes for 4.20-rc2 2018-11-10 08:58:48 -06:00
Kconfig xen: remove tmem driver 2019-07-17 08:09:58 +02:00
Makefile xen: remove tmem driver 2019-07-17 08:09:58 +02:00
manage.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
mcelog.c xen/mcelog: eliminate redundant setting of interface version 2018-08-20 14:46:18 -04:00
mem-reservation.c xen/balloon: add runtime control for scrubbing ballooned out pages 2018-09-14 08:51:10 -04:00
pci.c xen/pci: reserve MCFG areas earlier 2019-09-12 15:02:55 -04:00
pcpu.c
platform-pci.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 320 2019-06-05 17:37:05 +02:00
preempt.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 135 2019-05-30 11:25:15 -07:00
privcmd-buf.c xen/privcmd-buf.c: convert to use vm_map_pages_zero() 2019-05-14 09:47:50 -07:00
privcmd.c xen: avoid link error on ARM 2019-07-31 08:14:12 +02:00
privcmd.h xen: add new hypercall buffer mapping device 2018-06-22 08:26:42 +02:00
pvcalls-back.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
pvcalls-front.c xen: fixes for 5.2-rc3 2019-05-31 10:53:34 -07:00
pvcalls-front.h
swiotlb-xen.c swiotlb-xen: Convert to use macro 2019-09-06 09:20:50 -04:00
sys-hypervisor.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
time.c x86/paravirt: Use a single ops structure 2018-09-03 16:50:35 +02:00
xen-acpi-cpuhotplug.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 12 2019-05-21 11:28:45 +02:00
xen-acpi-memhotplug.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 12 2019-05-21 11:28:45 +02:00
xen-acpi-pad.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
xen-acpi-processor.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
xen-balloon.c xen: remove tmem driver 2019-07-17 08:09:58 +02:00
xen-front-pgdir-shbuf.c xen: Introduce shared buffer helpers for page directory... 2018-12-18 12:15:55 -05:00
xen-scsiback.c xen: fixes and features for 5.1-rc1 2019-03-11 17:08:14 -07:00
xen-stub.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 12 2019-05-21 11:28:45 +02:00
xlate_mmu.c xen: avoid link error on ARM 2019-07-31 08:14:12 +02:00