4b9380d92c
[ Upstream commit 0d4837fdb796f99369cf7691d33de1b856bcaf1f ] In our fault-injection testing, the variable "nblocks" in dbFree() can be zero when kmalloc_array() fails in dtSearch(). In this case, the variable "mp" in dbFree() would be NULL and then it is dereferenced in "write_metapage(mp)". The failure log is listed as follows: [ 13.824137] BUG: kernel NULL pointer dereference, address: 0000000000000020 ... [ 13.827416] RIP: 0010:dbFree+0x5f7/0x910 [jfs] [ 13.834341] Call Trace: [ 13.834540] <TASK> [ 13.834713] txFreeMap+0x7b4/0xb10 [jfs] [ 13.835038] txUpdateMap+0x311/0x650 [jfs] [ 13.835375] jfs_lazycommit+0x5f2/0xc70 [jfs] [ 13.835726] ? sched_dynamic_update+0x1b0/0x1b0 [ 13.836092] kthread+0x3c2/0x4a0 [ 13.836355] ? txLockFree+0x160/0x160 [jfs] [ 13.836763] ? kthread_unuse_mm+0x160/0x160 [ 13.837106] ret_from_fork+0x1f/0x30 [ 13.837402] </TASK> ... This patch adds a NULL check of "mp" before "write_metapage(mp)" is called. Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> Signed-off-by: Zixuan Fu <r33s3n6@gmail.com> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Signed-off-by: Sasha Levin <sashal@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.