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Filename Latest commit message Latest commit date
Cengiz Can 8278223554 blktrace: fix dereference after null check
[ Upstream commit 153031a301bb07194e9c37466cfce8eacb977621 ]

There was a recent change in blktrace.c that added a RCU protection to
`q->blk_trace` in order to fix a use-after-free issue during access.

However the change missed an edge case that can lead to dereferencing of
`bt` pointer even when it's NULL:

Coverity static analyzer marked this as a FORWARD_NULL issue with CID
1460458.

```
/kernel/trace/blktrace.c: 1904 in sysfs_blk_trace_attr_store()
1898            ret = 0;
1899            if (bt == NULL)
1900                    ret = blk_trace_setup_queue(q, bdev);
1901
1902            if (ret == 0) {
1903                    if (attr == &dev_attr_act_mask)
>>>     CID 1460458:  Null pointer dereferences  (FORWARD_NULL)
>>>     Dereferencing null pointer "bt".
1904                            bt->act_mask = value;
1905                    else if (attr == &dev_attr_pid)
1906                            bt->pid = value;
1907                    else if (attr == &dev_attr_start_lba)
1908                            bt->start_lba = value;
1909                    else if (attr == &dev_attr_end_lba)
```

Added a reassignment with RCU annotation to fix the issue.

Fixes: c780e86dd48 ("blktrace: Protect q->blk_trace with RCU")
Cc: stable@vger.kernel.org
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Cengiz Can <cengiz@kernel.wtf>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-03-12 13:00:10 +01:00
arch kvm: nVMX: VMWRITE checks unsupported field before read-only field 2020-03-05 16:43:52 +01:00
block block, bfq: do not insert oom queue into position tree 2020-03-12 13:00:08 +01:00
certs
crypto crypto: rename sm3-256 to sm3 in hash_algo_name 2020-02-28 17:22:26 +01:00
Documentation netfilter: nf_flowtable: fix documentation 2020-03-05 16:43:51 +01:00
drivers RDMA/core: Fix use of logical OR in get_new_pps 2020-03-12 13:00:09 +01:00
fs xfs: clear kernel only flags in XFS_IOC_ATTRMULTI_BY_HANDLE 2020-03-05 16:43:51 +01:00
include blktrace: Protect q->blk_trace with RCU 2020-03-05 16:43:52 +01:00
init kbuild: remove header compile test 2020-03-05 16:43:47 +01:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-28 17:22:20 +01:00
kernel blktrace: fix dereference after null check 2020-03-12 13:00:10 +01:00
lib kbuild: move headers_check rule to usr/include/Makefile 2020-03-05 16:43:47 +01:00
LICENSES
mm mm, thp: fix defrag setting if newline is not used 2020-03-05 16:43:51 +01:00
net netfilter: nft_tunnel: no need to call htons() when dumping ports 2020-03-05 16:43:50 +01:00
samples
scripts kbuild: move headers_check rule to usr/include/Makefile 2020-03-05 16:43:47 +01:00
security ima: ima/lsm policy rule loading logic bug fixes 2020-03-05 16:43:49 +01:00
sound ALSA: hda/realtek - Fix a regression for mute led on Lenovo Carbon X1 2020-03-12 13:00:08 +01:00
tools perf ui gtk: Add missing zalloc object 2020-03-05 16:43:50 +01:00
usr kbuild: fix 'No such file or directory' warning when cleaning 2020-03-12 13:00:09 +01:00
virt KVM: Check for a bad hva before dropping into the ghc slow path 2020-03-05 16:43:48 +01:00
.clang-format
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MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 17:22:19 +01:00
Makefile Linux 5.4.24 2020-03-05 16:43:52 +01:00
README

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.