Sagi Grimberg 64f5e9cdd7 nvmet: fix memory leak when removing namespaces and controllers concurrently
When removing a namespace, we add an NS_CHANGE async event, however if
the controller admin queue is removed after the event was added but not
yet processed, we won't free the aens, resulting in the below memory
leak [1].

Fix that by moving nvmet_async_event_free to the final controller
release after it is detached from subsys->ctrls ensuring no async
events are added, and modify it to simply remove all pending aens.

--
$ cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff888c1af2c000 (size 32):
  comm "nvmetcli", pid 5164, jiffies 4295220864 (age 6829.924s)
  hex dump (first 32 bytes):
    28 01 82 3b 8b 88 ff ff 28 01 82 3b 8b 88 ff ff  (..;....(..;....
    02 00 04 65 76 65 6e 74 5f 66 69 6c 65 00 00 00  ...event_file...
  backtrace:
    [<00000000217ae580>] nvmet_add_async_event+0x57/0x290 [nvmet]
    [<0000000012aa2ea9>] nvmet_ns_changed+0x206/0x300 [nvmet]
    [<00000000bb3fd52e>] nvmet_ns_disable+0x367/0x4f0 [nvmet]
    [<00000000e91ca9ec>] nvmet_ns_free+0x15/0x180 [nvmet]
    [<00000000a15deb52>] config_item_release+0xf1/0x1c0
    [<000000007e148432>] configfs_rmdir+0x555/0x7c0
    [<00000000f4506ea6>] vfs_rmdir+0x142/0x3c0
    [<0000000000acaaf0>] do_rmdir+0x2b2/0x340
    [<0000000034d1aa52>] do_syscall_64+0xa5/0x4d0
    [<00000000211f13bc>] entry_SYSCALL_64_after_hwframe+0x6a/0xdf

Fixes: a07b4970f464 ("nvmet: add a generic NVMe target")
Reported-by: David Milburn <dmilburn@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: David Milburn <dmilburn@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-05-27 07:12:40 +02:00
2020-04-18 13:28:09 -07:00
2020-05-21 08:22:20 -06:00
2020-04-11 09:46:12 -07:00
2020-04-16 10:45:47 -07:00
2020-04-17 09:48:50 -07:00
2020-02-24 22:43:18 -08:00
2020-04-19 14:35:30 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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