3a21777c6e
We had kernel panic, it is caused by unload module and last close confirmation. call trace: [1196029.743127] free_sess+0x15/0x50 [rtrs_client] [1196029.743128] rtrs_clt_close+0x4c/0x70 [rtrs_client] [1196029.743129] ? rnbd_clt_unmap_device+0x1b0/0x1b0 [rnbd_client] [1196029.743130] close_rtrs+0x25/0x50 [rnbd_client] [1196029.743131] rnbd_client_exit+0x93/0xb99 [rnbd_client] [1196029.743132] __x64_sys_delete_module+0x190/0x260 And in the crashdump confirmation kworker is also running. PID: 6943 TASK: ffff9e2ac8098000 CPU: 4 COMMAND: "kworker/4:2" #0 [ffffb206cf337c30] __schedule at ffffffff9f93f891 #1 [ffffb206cf337cc8] schedule at ffffffff9f93fe98 #2 [ffffb206cf337cd0] schedule_timeout at ffffffff9f943938 #3 [ffffb206cf337d50] wait_for_completion at ffffffff9f9410a7 #4 [ffffb206cf337da0] __flush_work at ffffffff9f08ce0e #5 [ffffb206cf337e20] rtrs_clt_close_conns at ffffffffc0d5f668 [rtrs_client] #6 [ffffb206cf337e48] rtrs_clt_close at ffffffffc0d5f801 [rtrs_client] #7 [ffffb206cf337e68] close_rtrs at ffffffffc0d26255 [rnbd_client] #8 [ffffb206cf337e78] free_sess at ffffffffc0d262ad [rnbd_client] #9 [ffffb206cf337e88] rnbd_clt_put_dev at ffffffffc0d266a7 [rnbd_client] The problem is both code path try to close same session, which lead to panic. To fix it, just skip the sess if the refcount already drop to 0. Fixes: f7a7a5c228d4 ("block/rnbd: client: main functionality") Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Reviewed-by: Gioh Kim <gi-oh.kim@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.