syzbot reported a slab-out-of-bounds/use-after-free issue, which was caused by accessing an already freed smc sock in fallback-specific callback functions of clcsock. This patch fixes the issue by restoring fallback-specific callback functions to original ones and resetting clcsock sk_user_data to NULL before freeing smc sock. Meanwhile, this patch introduces sk_callback_lock to make the access and assignment to sk_user_data mutually exclusive. Reported-by: syzbot+b425899ed22c6943e00b@syzkaller.appspotmail.com Fixes: 341adeec9ada ("net/smc: Forward wakeup to smc socket waitqueue after fallback") Link: https://lore.kernel.org/r/00000000000013ca8105d7ae3ada@google.com/ Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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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