Hello, If I merge Jens' for-next branch with Linus' master branch and boot the resulting kernel in a VM then the call trace shown below appears. This call trace does not appear when building and booting the code from Linus' master branch. Is this perhaps a regression? WARNING: CPU: 1 PID: 257 at block/blk-throttle.c:2128 blk+AF8-throtl+AF8-bio+-0xc00/0x1120 Modules linked in: floppy(+-) virtio+AF8-blk(+-) virtio+AF8-net net+AF8-failover failover i2c+AF8-piix4 pata+AF8-acpi CPU: 1 PID: 257 Comm: systemd-udevd Not tainted 4.20.0-rc5-dbg+- +ACM-1 Hardware name: QEMU Standard PC (i440FX +- PIIX, 1996), BIOS 1.10.2-1 04/01/2014 RIP: 0010:blk+AF8-throtl+AF8-bio+-0xc00/0x1120 Call Trace: ? create+AF8-task+AF8-io+AF8-context+-0x1a2/0x1e0 ? lock+AF8-downgrade+-0x2e0/0x2e0 ? kasan+AF8-check+AF8-read+-0x11/0x20 ? do+AF8-raw+AF8-spin+AF8-unlock+-0xa8/0x140 ? preempt+AF8-count+AF8-sub+-0x18/0xd0 generic+AF8-make+AF8-request+AF8-checks+-0x432/0xcc0 ? trace+AF8-event+AF8-raw+AF8-event+AF8-block+AF8-rq+AF8-requeue+-0x290/0x290 ? +AF8AXw-lock+AF8-acquire+-0x5b0/0x17e0 ? +AF8AXw-bio+AF8-associate+AF8-blkg.isra.33+-0x1d0/0x3c0 generic+AF8-make+AF8-request+-0x151/0x950 ? blk+AF8-queue+AF8-enter+-0x7e0/0x7e0 submit+AF8-bio+-0x9b/0x250 ? submit+AF8-bio+-0x9b/0x250 ? generic+AF8-make+AF8-request+-0x950/0x950 ? guard+AF8-bio+AF8-eod+-0x120/0x2d0 submit+AF8-bh+AF8-wbc+-0x2df/0x310 block+AF8-read+AF8-full+AF8-page+-0x34c/0x4c0 ? I+AF8-BDEV+-0x20/0x20 ? +AF8AXw-bread+AF8-gfp+-0x170/0x170 ? add+AF8-to+AF8-page+AF8-cache+AF8-locked+-0x20/0x20 ? blkdev+AF8-writepages+-0x10/0x10 ? blkdev+AF8-writepages+-0x10/0x10 blkdev+AF8-readpage+-0x18/0x20 do+AF8-read+AF8-cache+AF8-page+-0x5ed/0xbf0 ? blkdev+AF8-writepages+-0x10/0x10 ? find+AF8-valid+AF8-gpt+-0x1a8/0x8b0 ? efi+AF8-partition+-0x147/0x6c1 ? check+AF8-partition+-0x1b2/0x314 ? blkdev+AF8-get+-0x1f2/0x5a0 ? +AF8AXw-device+AF8-add+AF8-disk+-0x6c1/0x7e0 ? device+AF8-add+AF8-disk+-0x13/0x20 ? pagecache+AF8-get+AF8-page+-0x420/0x420 ? driver+AF8-probe+AF8-device+-0x118/0x180 ? +AF8AXw-driver+AF8-attach+-0x167/0x190 ? bus+AF8-for+AF8-each+AF8-dev+-0x105/0x160 ? driver+AF8-attach+-0x2b/0x30 ? bus+AF8-add+AF8-driver+-0x23d/0x350 ? driver+AF8-register+-0xdc/0x160 ? register+AF8-virtio+AF8-driver+-0x3c/0x60 ? init+-0x51/0x1000 +AFs-virtio+AF8-blk+AF0 ? do+AF8-one+AF8-initcall+-0xb4/0x3a1 ? do+AF8-init+AF8-module+-0x103/0x360 ? load+AF8-module+-0x443e/0x4630 ? +AF8AXw-do+AF8-sys+AF8-finit+AF8-module+-0x12d/0x1b0 ? +AF8AXw-x64+AF8-sys+AF8-finit+AF8-module+-0x43/0x50 ? do+AF8-syscall+AF8-64+-0x71/0x210 ? entry+AF8-SYSCALL+AF8-64+AF8-after+AF8-hwframe+-0x49/0xbe ? match+AF8-held+AF8-lock+-0x20/0x250 ? match+AF8-held+AF8-lock+-0x35/0x250 ? blkdev+AF8-writepages+-0x10/0x10 read+AF8-cache+AF8-page+-0x3a/0x50 read+AF8-dev+AF8-sector+-0x64/0x170 read+AF8-lba+-0x1f9/0x3a0 ? msdos+AF8-partition+-0x1370/0x1370 ? find+AF8-valid+AF8-gpt+-0x1a8/0x8b0 ? kmem+AF8-cache+AF8-alloc+AF8-trace+-0x151/0x340 ? find+AF8-valid+AF8-gpt+-0x1a8/0x8b0 find+AF8-valid+AF8-gpt+-0x1c6/0x8b0 ? is+AF8-gpt+AF8-valid.part.5+-0x640/0x640 ? +AF8AXw-alloc+AF8-pages+AF8-nodemask+-0x1c4/0x4d0 ? lockdep+AF8-hardirqs+AF8-on+-0x182/0x260 ? get+AF8-page+AF8-from+AF8-freelist+-0x648/0x2070 ? mark+AF8-lock+-0x69/0x8d0 ? trace+AF8-hardirqs+AF8-on+-0x24/0x130 ? kasan+AF8-unpoison+AF8-shadow+-0x35/0x50 ? get+AF8-page+AF8-from+AF8-freelist+-0x648/0x2070 ? +AF8AXw-asan+AF8-loadN+-0xf/0x20 ? widen+AF8-string+-0x73/0x170 ? +AF8AXw-asan+AF8-loadN+-0xf/0x20 ? widen+AF8-string+-0x73/0x170 ? get+AF8-page+AF8-from+AF8-freelist+-0x1eea/0x2070 ? set+AF8-precision+-0x90/0x90 ? string+-0x135/0x180 efi+AF8-partition+-0x147/0x6c1 ? format+AF8-decode+-0xce/0x550 ? enable+AF8-ptr+AF8-key+AF8-workfn+-0x30/0x30 ? find+AF8-valid+AF8-gpt+-0x8b0/0x8b0 ? vsnprintf+-0x11d/0x820 ? pointer+-0x4d0/0x4d0 ? snprintf+-0x88/0xa0 ? snprintf+-0x88/0xa0 ? vsprintf+-0x20/0x20 ? find+AF8-valid+AF8-gpt+-0x8b0/0x8b0 check+AF8-partition+-0x1b2/0x314 rescan+AF8-partitions+-0x13b/0x440 +AF8AXw-blkdev+AF8-get+-0x61f/0x930 ? check+AF8-disk+AF8-change+-0xa0/0xa0 ? lock+AF8-downgrade+-0x2e0/0x2e0 ? var+AF8-wake+AF8-function+-0x90/0x90 blkdev+AF8-get+-0x1f2/0x5a0 ? preempt+AF8-count+AF8-sub+-0x18/0xd0 ? +AF8-raw+AF8-spin+AF8-unlock+-0x31/0x50 ? bd+AF8-may+AF8-claim+-0x80/0x80 ? bdget+-0x26b/0x280 ? blkdev+AF8-writepage+-0x20/0x20 ? kasan+AF8-check+AF8-read+-0x11/0x20 ? kobject+AF8-put+-0x23/0x220 +AF8AXw-device+AF8-add+AF8-disk+-0x6c1/0x7e0 ? blk+AF8-alloc+AF8-devt+-0x150/0x150 ? +AF8AXw-asan+AF8-storeN+-0x12/0x20 device+AF8-add+AF8-disk+-0x13/0x20 virtblk+AF8-probe+-0x839/0xace +AFs-virtio+AF8-blk+AF0 ? virtblk+AF8-restore+-0xd0/0xd0 +AFs-virtio+AF8-blk+AF0 ? mutex+AF8-unlock+-0x12/0x20 ? kernfs+AF8-activate+-0xd0/0xe0 ? kasan+AF8-check+AF8-write+-0x14/0x20 ? kernfs+AF8-put+-0x2c/0x280 ? vring+AF8-transport+AF8-features+-0x19/0x70 ? vp+AF8-finalize+AF8-features+-0xe6/0x160 ? vp+AF8-get+AF8-status+-0x29/0x30 ? virtio+AF8-finalize+AF8-features+-0xbe/0xe0 virtio+AF8-dev+AF8-probe+-0x27d/0x390 really+AF8-probe+-0x191/0x560 ? driver+AF8-probe+AF8-device+-0x180/0x180 driver+AF8-probe+AF8-device+-0x118/0x180 ? driver+AF8-probe+AF8-device+-0x180/0x180 +AF8AXw-driver+AF8-attach+-0x167/0x190 bus+AF8-for+AF8-each+AF8-dev+-0x105/0x160 ? subsys+AF8-dev+AF8-iter+AF8-exit+-0x10/0x10 ? kasan+AF8-check+AF8-read+-0x11/0x20 ? preempt+AF8-count+AF8-sub+-0x18/0xd0 ? +AF8-raw+AF8-spin+AF8-unlock+-0x31/0x50 driver+AF8-attach+-0x2b/0x30 bus+AF8-add+AF8-driver+-0x23d/0x350 driver+AF8-register+-0xdc/0x160 ? 0xffffffffa0070000 register+AF8-virtio+AF8-driver+-0x3c/0x60 init+-0x51/0x1000 +AFs-virtio+AF8-blk+AF0 do+AF8-one+AF8-initcall+-0xb4/0x3a1 ? trace+AF8-event+AF8-raw+AF8-event+AF8-initcall+AF8-finish+-0x120/0x120 ? kasan+AF8-unpoison+AF8-shadow+-0x35/0x50 ? +AF8AXw-asan+AF8-register+AF8-globals+-0x7b/0xa0 do+AF8-init+AF8-module+-0x103/0x360 load+AF8-module+-0x443e/0x4630 ? module+AF8-frob+AF8-arch+AF8-sections+-0x20/0x20 ? vfs+AF8-read+-0xe6/0x1e0 ? kernel+AF8-read+-0x79/0xa0 ? kasan+AF8-check+AF8-write+-0x14/0x20 ? kernel+AF8-read+AF8-file+-0x259/0x310 ? do+AF8-mmap+-0x431/0x6c0 +AF8AXw-do+AF8-sys+AF8-finit+AF8-module+-0x12d/0x1b0 ? +AF8AXw-do+AF8-sys+AF8-finit+AF8-module+-0x12d/0x1b0 ? +AF8AXw-do+AF8-sys+AF8-init+AF8-module+-0x200/0x200 ? kasan+AF8-check+AF8-write+-0x14/0x20 ? fput+-0x1d/0xc0 ? do+AF8-syscall+AF8-64+-0x19/0x210 ? entry+AF8-SYSCALL+AF8-64+AF8-after+AF8-hwframe+-0x49/0xbe +AF8AXw-x64+AF8-sys+AF8-finit+AF8-module+-0x43/0x50 do+AF8-syscall+AF8-64+-0x71/0x210 entry+AF8-SYSCALL+AF8-64+AF8-after+AF8-hwframe+-0x49/0xbe
