7bd4d8645a
Otherwise, we might run into an abort via bdrv_co_yield_to_drain() (can at least happen when a disk with iothread is used): > #0 0x00007fef4f5dece1 __GI_raise (libc.so.6 + 0x3bce1) > #1 0x00007fef4f5c8537 __GI_abort (libc.so.6 + 0x25537) > #2 0x00005641bce3c71f error_exit (qemu-system-x86_64 + 0x80371f) > #3 0x00005641bce3d02b qemu_mutex_unlock_impl (qemu-system-x86_64 + 0x80402b) > #4 0x00005641bcd51655 bdrv_co_yield_to_drain (qemu-system-x86_64 + 0x718655) > #5 0x00005641bcd52de8 bdrv_do_drained_begin (qemu-system-x86_64 + 0x719de8) > #6 0x00005641bcd47e07 blk_drain (qemu-system-x86_64 + 0x70ee07) > #7 0x00005641bcd498cd blk_unref (qemu-system-x86_64 + 0x7108cd) > #8 0x00005641bcd31e6f block_job_free (qemu-system-x86_64 + 0x6f8e6f) > #9 0x00005641bcd32d65 job_unref (qemu-system-x86_64 + 0x6f9d65) > #10 0x00005641bcd93b3d pvebackup_co_complete_stream (qemu-system-x86_64 + 0x75ab3d) > #11 0x00005641bce4e353 coroutine_trampoline (qemu-system-x86_64 + 0x815353) Signed-off-by: Fabian Ebner <f.ebner@proxmox.com> Acked-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
77 lines
2.7 KiB
Diff
77 lines
2.7 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Fabian Ebner <f.ebner@proxmox.com>
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Date: Wed, 25 May 2022 13:59:38 +0200
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Subject: [PATCH] PVE-Backup: ensure jobs in di_list are referenced
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Ensures that qmp_backup_cancel doesn't pick a job that's already been
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freed. With unlucky timings it seems possible that:
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1. job_exit -> job_completed -> job_finalize_single starts
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2. pvebackup_co_complete_stream gets spawned in completion callback
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3. job finalize_single finishes -> job's refcount hits zero -> job is
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freed
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4. qmp_backup_cancel comes in and locks backup_state.backup_mutex
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before pvebackup_co_complete_stream can remove the job from the
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di_list
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5. qmp_backup_cancel will pick a job that's already been freed
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Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
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Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
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---
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pve-backup.c | 13 +++++++++++++
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1 file changed, 13 insertions(+)
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Index: pve-qemu-kvm-6.2.0/pve-backup.c
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===================================================================
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--- pve-qemu-kvm-6.2.0.orig/pve-backup.c
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+++ pve-qemu-kvm-6.2.0/pve-backup.c
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@@ -316,6 +316,14 @@ static void coroutine_fn pvebackup_co_co
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}
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}
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+ if (di->job) {
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+ AioContext *ctx = di->job->job.aio_context;
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+ aio_context_acquire(ctx);
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+ job_unref(&di->job->job);
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+ di->job = NULL;
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+ aio_context_release(ctx);
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+ }
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+
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// remove self from job list
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backup_state.di_list = g_list_remove(backup_state.di_list, di);
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@@ -491,9 +499,12 @@ static void create_backup_jobs_bh(void *
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bitmap_mode, false, NULL, &perf, BLOCKDEV_ON_ERROR_REPORT, BLOCKDEV_ON_ERROR_REPORT,
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JOB_DEFAULT, pvebackup_complete_cb, di, backup_state.txn, &local_err);
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- aio_context_release(aio_context);
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-
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di->job = job;
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+ if (job) {
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+ job_ref(&job->job);
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+ }
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+
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+ aio_context_release(aio_context);
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if (!job || local_err) {
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error_setg(errp, "backup_job_create failed: %s",
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@@ -521,12 +532,16 @@ static void create_backup_jobs_bh(void *
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di->target = NULL;
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}
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- if (!canceled && di->job) {
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+ if (di->job) {
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AioContext *ctx = di->job->job.aio_context;
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aio_context_acquire(ctx);
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- job_cancel_sync(&di->job->job, true);
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+ if (!canceled) {
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+ job_cancel_sync(&di->job->job, true);
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+ canceled = true;
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+ }
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+ job_unref(&di->job->job);
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+ di->job = NULL;
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aio_context_release(ctx);
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- canceled = true;
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}
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}
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}
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