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[ Upstream commit8511a653e9] Calculation of qp mtt size (in function mlx4_RST2INIT_wrapper) ultimately depends on function roundup_pow_of_two. If the amount of memory required by the QP is less than one page, roundup_pow_of_two is called with argument zero. In this case, the roundup_pow_of_two result is undefined. Calling roundup_pow_of_two with a zero argument resulted in the following stack trace: UBSAN: Undefined behaviour in ./include/linux/log2.h:61:13 shift exponent 64 is too large for 64-bit type 'long unsigned int' CPU: 4 PID: 26939 Comm: rping Tainted: G OE 4.19.0-rc1 Hardware name: Supermicro X9DR3-F/X9DR3-F, BIOS 3.2a 07/09/2015 Call Trace: dump_stack+0x9a/0xeb ubsan_epilogue+0x9/0x7c __ubsan_handle_shift_out_of_bounds+0x254/0x29d ? __ubsan_handle_load_invalid_value+0x180/0x180 ? debug_show_all_locks+0x310/0x310 ? sched_clock+0x5/0x10 ? sched_clock+0x5/0x10 ? sched_clock_cpu+0x18/0x260 ? find_held_lock+0x35/0x1e0 ? mlx4_RST2INIT_QP_wrapper+0xfb1/0x1440 [mlx4_core] mlx4_RST2INIT_QP_wrapper+0xfb1/0x1440 [mlx4_core] Fix this by explicitly testing for zero, and returning one if the argument is zero (assuming that the next higher power of 2 in this case should be one). Fixes:c82e9aa0a8("mlx4_core: resource tracking for HCA resources used by guests") Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.
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.