)]}' { "commit": "7e573b660fefdebd21cb755d0d34bb5942fd3af3", "tree": "737fde9bfdd10a3427e725f8143462da8a214ed7", "parents": [ "ba20257d9b45c28f23a66b3f79bebffd6322ff76" ], "author": { "name": "Fabiano Rosas", "email": "farosas@suse.de", "time": "Wed Jun 03 16:38:13 2026 -0300" }, "committer": { "name": "Kevin Wolf", "email": "kwolf@redhat.com", "time": "Wed Jun 10 12:12:48 2026 +0200" }, "message": "qed: Don\u0027t try to flush during incoming migration\n\nIt\u0027s not possible to access the image file while there is an incoming\nmigration in progress, the QEMU process doesn\u0027t hold any locks to the\nstorage at this point so nodes are inactive. Attempting to flush leads\nto an assert at bdrv_co_write_req_prepare():\n\n assert(!(bs-\u003eopen_flags \u0026 BDRV_O_INACTIVE))\n\nThe issue is reproducible by running iotest 181 on a host under cpu\nload. The migration must coincide with the header already containing\nthe QED_F_NEED_CHECK flag.\n\nThe sequence of events is as follows, with the respective call stacks\nreferenced below:\n\nDuring block device init, bdrv_qed_attach_aio_context() starts the\n\u0027need_check\u0027 timer. The timer will not fire during incoming migration\nas it uses QEMU_CLOCK_VIRTUAL (to avoid this very issue, as the code\ncomment indicates). (0)\n\nHowever, there\u0027s still bdrv_qed_drain_begin() which uses the fact that\nthe timer is live to decide whether to start the\nqed_need_check_timer_entry() directly. (1)\n\nThe qed_need_check_timer_entry() eventually calls into\nqed_write_header() -\u003e bdrv_co_pwrite() leading to the assert. (2)\n\nSkip creating the \u0027need_check\u0027 timer whenever the image is inactive.\n\nThe stacks:\n\n(0) \u003d\u003d issues timer_mod \u003d\u003d\n #6 in qed_start_need_check_timer at ../block/qed.c:340\n #7 in bdrv_qed_attach_aio_context at ../block/qed.c:373\n #8 in bdrv_qed_do_open at ../block/qed.c:556\n #9 in bdrv_qed_open_entry at ../block/qed.c:582\n #10 in coroutine_trampoline at ../util/coroutine-ucontext.c:175\n #0 in qemu_coroutine_switch\u003c+120\u003e at ../util/coroutine-ucontext.c:321\n #1 in qemu_aio_coroutine_enter\u003c+356\u003e at ../util/qemu-coroutine.c:293\n #2 in aio_co_enter\u003c+179\u003e at ../util/async.c:710\n #3 in aio_co_wake\u003c+53\u003e at ../util/async.c:695\n #4 in thread_pool_co_cb\u003c+47\u003e at ../util/thread-pool.c:283\n #5 in thread_pool_completion_bh\u003c+241\u003e at ../util/thread-pool.c:202\n #6 in aio_bh_call\u003c+109\u003e at ../util/async.c:173\n #7 in aio_bh_poll\u003c+299\u003e at ../util/async.c:220\n #8 in aio_poll\u003c+690\u003e at ../util/aio-posix.c:745\n #9 in bdrv_qed_open\u003c+392\u003e at ../block/qed.c:607\n #10 in bdrv_open_driver\u003c+327\u003e at ../block.c:1678\n #11 in bdrv_open_common\u003c+1619\u003e at ../block.c:2008\n #12 in bdrv_open_inherit\u003c+2556\u003e at ../block.c:4191\n #13 in bdrv_open\u003c+118\u003e at ../block.c:4286\n #14 in blk_new_open\u003c+199\u003e at ../block/block-backend.c:458\n #15 in blockdev_init\u003c+2011\u003e at ../blockdev.c:612\n #16 in drive_new\u003c+3008\u003e at ../blockdev.c:1008\n #17 in drive_init_func\u003c+51\u003e at ../system/vl.c:662\n #18 in qemu_opts_foreach\u003c+227\u003e at ../util/qemu-option.c:1148\n #19 in configure_blockdev\u003c+350\u003e at ../system/vl.c:721\n #20 in qemu_create_early_backends\u003c+343\u003e at ../system/vl.c:2076\n #21 in qemu_init\u003c+12483\u003e at ../system/vl.c:3778\n #22 in main\u003c+46\u003e at ../system/main.c:71\n\n(1) \u003d\u003d sees timer_pending \u003d\u003d\n #6 in bdrv_qed_drain_begin at ../block/qed.c:391\n #7 in bdrv_do_drained_begin at ../block/io.c:366\n #8 in bdrv_do_drained_begin_quiesce at ../block/io.c:386\n #9 in bdrv_child_cb_drained_begin at ../block.c:1207\n #10 in bdrv_parent_drained_begin_single at ../block/io.c:133\n #11 in bdrv_parent_drained_begin at ../block/io.c:64\n #12 in bdrv_do_drained_begin at ../block/io.c:364\n #13 in bdrv_drained_begin at ../block/io.c:393\n #14 in blk_drain at ../block/block-backend.c:2101\n #15 in blk_unref at ../block/block-backend.c:544\n #16 in bdrv_open_inherit at ../block.c:4197\n #17 in bdrv_open at ../block.c:4286\n #18 in blk_new_open at ../block/block-backend.c:458\n #19 in blockdev_init at ../blockdev.c:612\n #20 in drive_new at ../blockdev.c:1008\n #21 in drive_init_func at ../system/vl.c:662\n #22 in qemu_opts_foreach at ../util/qemu-option.c:1148\n #23 in configure_blockdev at ../system/vl.c:721\n #24 in qemu_create_early_backends at ../system/vl.c:2076\n #25 in qemu_init at ../system/vl.c:3778\n #26 in main at ../system/main.c:71\n\n(2) \u003d\u003d crashes \u003d\u003d\n #5 in __assert_fail (assertion\u003d\"!(bs-\u003eopen_flags \u0026 BDRV_O_INACTIVE)\", file\u003d\"../block/io.c\", line\u003d1977\n #6 in bdrv_co_write_req_prepare at ../block/io.c:1977\n #7 in bdrv_aligned_pwritev at ../block/io.c:2099\n #8 in bdrv_co_pwritev_part at ../block/io.c:2316\n #9 in bdrv_co_pwritev at ../block/io.c:2233\n #10 in bdrv_co_pwrite at ../include/block/block_int-io.h:77\n #11 in qed_write_header at ../block/qed.c:128\n #12 in qed_need_check_timer at ../block/qed.c:305\n #13 in qed_need_check_timer_entry at ../block/qed.c:319\n\nNote that this issue is not exactly the same as what\u0027s been reported\nin Gitlab, but given how easily this reproduces, I imagine it has to\nbe happening in that setup as well.\n\nLink: https://gitlab.com/qemu-project/qemu/-/work_items/3515\nSigned-off-by: Fabiano Rosas \u003cfarosas@suse.de\u003e\nMessage-ID: \u003c20260603193813.2327596-1-farosas@suse.de\u003e\nReviewed-by: Stefan Hajnoczi \u003cstefanha@redhat.com\u003e\nReviewed-by: Kevin Wolf \u003ckwolf@redhat.com\u003e\nSigned-off-by: Kevin Wolf \u003ckwolf@redhat.com\u003e\n", "tree_diff": [ { "type": "modify", "old_id": "da23a83d623a2e84dc2b10f79e672354b183b02b", "old_mode": 33188, "old_path": "block/qed.c", "new_id": "0eccfa21c98b6af6b95a51363eeae8f5d8f73526", "new_mode": 33188, "new_path": "block/qed.c" } ] }