ba439a6cbf
The following KASAN warning was printed when booting a 64-bit kernel on some systems with Intel CPUs: [ 44.512826] ================================================================== [ 44.520165] BUG: KASAN: stack-out-of-bounds in find_first_bit+0xb0/0xc0 [ 44.526786] Read of size 8 at addr ffff88041e02fc50 by task kworker/0:2/124 [ 44.535253] CPU: 0 PID: 124 Comm: kworker/0:2 Tainted: G X --------- --- 4.18.0-12.el8.x86_64+debug #1 [ 44.545858] Hardware name: Intel Corporation PURLEY/PURLEY, BIOS BKVDTRL1.86B.0005.D08.1712070559 12/07/2017 [ 44.555682] Workqueue: events work_for_cpu_fn [ 44.560043] Call Trace: [ 44.562502] dump_stack+0x9a/0xe9 [ 44.565832] print_address_description+0x65/0x22e [ 44.570683] ? find_first_bit+0xb0/0xc0 [ 44.570689] kasan_report.cold.6+0x92/0x19f [ 44.578726] find_first_bit+0xb0/0xc0 [ 44.578737] adf_probe+0x9eb/0x19a0 [qat_c62x] [ 44.578751] ? adf_remove+0x110/0x110 [qat_c62x] [ 44.591490] ? mark_held_locks+0xc8/0x140 [ 44.591498] ? _raw_spin_unlock+0x30/0x30 [ 44.591505] ? trace_hardirqs_on_caller+0x381/0x570 [ 44.604418] ? adf_remove+0x110/0x110 [qat_c62x] [ 44.604427] local_pci_probe+0xd4/0x180 [ 44.604432] ? pci_device_shutdown+0x110/0x110 [ 44.617386] work_for_cpu_fn+0x51/0xa0 [ 44.621145] process_one_work+0x8fe/0x16e0 [ 44.625263] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 44.629799] ? lock_acquire+0x14c/0x400 [ 44.633645] ? move_linked_works+0x12e/0x2a0 [ 44.637928] worker_thread+0x536/0xb50 [ 44.641690] ? __kthread_parkme+0xb6/0x180 [ 44.645796] ? process_one_work+0x16e0/0x16e0 [ 44.650160] kthread+0x30c/0x3d0 [ 44.653400] ? kthread_create_worker_on_cpu+0xc0/0xc0 [ 44.658457] ret_from_fork+0x3a/0x50 [ 44.663557] The buggy address belongs to the page: [ 44.668350] page:ffffea0010780bc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0 [ 44.676356] flags: 0x17ffffc0000000() [ 44.680023] raw: 0017ffffc0000000 ffffea0010780bc8 ffffea0010780bc8 0000000000000000 [ 44.687769] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 44.695510] page dumped because: kasan: bad access detected [ 44.702578] Memory state around the buggy address: [ 44.707372] ffff88041e02fb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 44.714593] ffff88041e02fb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 44.721810] >ffff88041e02fc00: 00 00 00 00 00 00 f1 f1 f1 f1 04 f2 f2 f2 f2 f2 [ 44.729028] ^ [ 44.734864] ffff88041e02fc80: f2 f2 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00 00 [ 44.742082] ffff88041e02fd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 44.749299] ================================================================== Looking into the code: int ret, bar_mask; : for_each_set_bit(bar_nr, (const unsigned long *)&bar_mask, It is casting a 32-bit integer pointer to a 64-bit unsigned long pointer. There are two problems here. First, the 32-bit pointer address may not be 64-bit aligned. Secondly, it is accessing an extra 4 bytes. This is fixed by changing the bar_mask type to unsigned long. Cc: <stable@vger.kernel.org> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
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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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.