Summary: ntfa: fix mutiple mutex lock/unlock on ntfa_cb in saNtfNotificationSend [#1263]. Review request for Trac Ticket(s): #1263 Peer Reviewer(s): Lennart, Minh, Mathivanan. Pull request to: <<LIST THE PERSON WITH PUSH ACCESS HERE>> Affected branch(es): ALl Development branch: <<IF ANY GIVE THE REPO URL>>
-------------------------------- Impacted area Impact y/n -------------------------------- Docs n Build system n RPM/packaging n Configuration files n Startup scripts n SAF services y OpenSAF services n Core libraries n Samples n Tests n Other n Comments (indicate scope for each "y" above): --------------------------------------------- Please see the commit log below. changeset 312ec05120bab63422a34883884a70115540661e Author: [email protected] Date: Thu, 19 Mar 2015 11:05:57 +0530 ntfa: fix mutiple mutex lock/unlock on ntfa_cb in saNtfNotificationSend [#1263] In a multithreaded application,saNtfFinalize() may hang forever leading to deadlock, if one thread tries to call finalize the handle, when other thread is trying to send a notification. The reason is saNtfNotificationSend() API takes mutex_lock() on ntfa_cb three times: -In the first lock/unlock,it retrieves client record. -In the second lock/unlock, it verifies notification parameters. -In the third lock/unlock, it sets notificationId that it has got from ntfs. In saNtfFinalize() API also after receving response from the NTFS, it tries to free all records for this client and also it releases allocated memory for the notifications. If saNtfFinalize() is called for the same client from one thread for which Send() is in progress in another thread, saNtfFinalize() may get lock on ntfa_cb and it will try to destroy all the records for this client. But here it will not be able to destroy the record as Send() API is still using records in the lock free region. Thus after taking a lock on ntfa_cb, saNtfFinalize() blocks itself for the client record to be released by Send(). Since Send() is in progress, in between it will also try to again take lock on ntfa_cb, but it will not get as it already owned by saNtfFinalize() which is already blocked because of client resources owned by Send(). As a solution, multiple locks should be avoided in the Send() API. Only while retrieving client record and notificationHanndle record it should use lock on ntfa_cb. The reason is saNtfFinalize() will anyway wait for the resoureces taken by Send() to be released and thus it will not free the memory. In the worst case, saNtfFinalize() will complete in NTFS_WAIT_TIME, but there will not be any deadlock situation. Complete diffstat: ------------------ osaf/libs/agents/saf/ntfa/ntfa_api.c | 10 ++++------ 1 files changed, 4 insertions(+), 6 deletions(-) Testing Commands: ----------------- Tested with the application attached in this ticket in community. Testing, Expected Results: -------------------------- saNtfFinalize() will not hang and in the worst case it will complete in NTFS_WAIT_TIME. Conditions of Submission: ------------------------- Ack from atleast two reviewers. Arch Built Started Linux distro ------------------------------------------- mips n n mips64 n n x86 n y x86_64 y y powerpc n n powerpc64 n n Reviewer Checklist: ------------------- [Submitters: make sure that your review doesn't trigger any checkmarks!] Your checkin has not passed review because (see checked entries): ___ Your RR template is generally incomplete; it has too many blank entries that need proper data filled in. ___ You have failed to nominate the proper persons for review and push. ___ Your patches do not have proper short+long header ___ You have grammar/spelling in your header that is unacceptable. ___ You have exceeded a sensible line length in your headers/comments/text. ___ You have failed to put in a proper Trac Ticket # into your commits. ___ You have incorrectly put/left internal data in your comments/files (i.e. internal bug tracking tool IDs, product names etc) ___ You have not given any evidence of testing beyond basic build tests. 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