From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: [PATCH 0/5] blkdebug: fix racing condition when iterating on
Date: Thu, 8 Apr 2021 17:59:08 +0200 [thread overview]
Message-ID: <20210408155913.53235-1-eesposit@redhat.com> (raw)
When qemu_coroutine_enter is executed in a loop
(even QEMU_FOREACH_SAFE), the new routine can modify the list,
for example removing an element, causing problem when control
is given back to the caller that continues iterating on the same list.
Patch 1 solves the issue in blkdebug_debug_resume by restarting
the list walk after every coroutine_enter if list has to be fully iterated.
Patches 2,3,4 aim to fix blkdebug_debug_event by gathering
all actions that the rules make in a counter and invoking
the respective coroutine_yeld only after processing all requests.
Patch 5 adds a lock to protect rules and suspended_reqs.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Emanuele Giuseppe Esposito (5):
blkdebug: refactor removal of a suspended request
blkdebug: move post-resume handling to resume_req_by_tag
blkdebug: track all actions
blkdebug: do not suspend in the middle of QLIST_FOREACH_SAFE
blkdebug: protect rules and suspended_reqs with a lock
block/blkdebug.c | 113 +++++++++++++++++++++++++++++++++--------------
1 file changed, 79 insertions(+), 34 deletions(-)
--
2.30.2
next reply other threads:[~2021-04-08 16:01 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 15:59 Emanuele Giuseppe Esposito [this message]
2021-04-08 15:59 ` [PATCH 1/5] blkdebug: refactor removal of a suspended request Emanuele Giuseppe Esposito
2021-04-08 15:59 ` [PATCH 2/5] blkdebug: move post-resume handling to resume_req_by_tag Emanuele Giuseppe Esposito
2021-04-08 15:59 ` [PATCH 3/5] blkdebug: track all actions Emanuele Giuseppe Esposito
2021-04-08 15:59 ` [PATCH 4/5] blkdebug: do not suspend in the middle of QLIST_FOREACH_SAFE Emanuele Giuseppe Esposito
2021-04-13 7:48 ` Paolo Bonzini
2021-04-08 15:59 ` [PATCH 5/5] blkdebug: protect rules and suspended_reqs with a lock Emanuele Giuseppe Esposito
2021-04-13 7:50 ` [PATCH 0/5] blkdebug: fix racing condition when iterating on Paolo Bonzini
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