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c9c4c070e0
Prevent calling roundup_pow_of_two() with value of 0 as it causes the
below UBSAN note.
Move this code and its few extra related lines to be called only when
it's really applicable.
UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
shift exponent 64 is too large for 64-bit type 'long unsigned int'
CPU: 15 PID: 1639 Comm: live_migration Not tainted 6.1.0-rc4 #1116
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x45/0x59
ubsan_epilogue+0x5/0x36
__ubsan_handle_shift_out_of_bounds.cold+0x61/0xef
? lock_is_held_type+0x98/0x110
? rcu_read_lock_sched_held+0x3f/0x70
mlx5vf_create_rc_qp.cold+0xe4/0xf2 [mlx5_vfio_pci]
mlx5vf_start_page_tracker+0x769/0xcd0 [mlx5_vfio_pci]
vfio_device_fops_unl_ioctl+0x63f/0x700 [vfio]
__x64_sys_ioctl+0x433/0x9a0
do_syscall_64+0x3d/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
Fixes: 79c3cf2799 ("vfio/mlx5: Init QP based resources for dirty tracking")
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230108154427.32609-2-yishaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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.