• Jack Morgenstein's avatar
    net/mlx4_core: Fix qp mtt size calculation · 8511a653
    Jack Morgenstein authored
    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: c82e9aa0 ("mlx4_core: resource tracking for HCA resources used by guests")
    Signed-off-by: default avatarJack Morgenstein <jackm@dev.mellanox.co.il>
    Signed-off-by: default avatarTariq Toukan <tariqt@mellanox.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    8511a653
resource_tracker.c 132 KB