Jack Morgenstein b03bcde962 IB/mlx4: Fix integer overflow when calculating optimal MTT size ... When the kernel was compiled using the UBSAN option, we saw the following stack trace: [ 1184.827917] UBSAN: Undefined behaviour in drivers/infiniband/hw/mlx4/mr.c:349:27 [ 1184.828114] signed integer overflow: [ 1184.828247] -2147483648 - 1 cannot be represented in type 'int' The problem was caused by calling round_up in procedure mlx4_ib_umem_calc_optimal_mtt_size (on line 349, as noted in the stack trace) with the second parameter (1 << block_shift) (which is an int). The second parameter should have been (1ULL << block_shift) (which is an unsigned long long). (1 << block_shift) is treated by the compiler as an int (because 1 is an integer). Now, local variable block_shift is initialized to 31. If block_shift is 31, 1 << block_shift is 1 << 31 = 0x80000000=-214748368. This is the most negative int value. Inside the round_up macro, there is a cast applied to ((1 << 31) - 1). However, this cast is applied AFTER ((1 << 31) - 1) is calculated. Since (1 << 31) is treated as an int, we get the negative overflow identified by UBSAN in the process of calculating ((1 << 31) - 1). The fix is to change (1 << block_shift) to (1ULL << block_shift) on line 349. Fixes: 9901abf583 ("IB/mlx4: Use optimal numbers of MTT entries") Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>		2018-05-03 15:31:43 -04:00
..
core	IB/core: Make ib_mad_client_id atomic	2018-04-30 13:07:28 -04:00
hw	IB/mlx4: Fix integer overflow when calculating optimal MTT size	2018-05-03 15:31:43 -04:00
sw	IB/rxe: avoid double kfree_skb	2018-04-27 14:20:47 -04:00
ulp	IB/ipoib: fix ipoib_start_xmit()'s return type	2018-04-27 14:07:30 -04:00
Kconfig	IB: make INFINIBAND_ADDR_TRANS configurable	2018-04-27 11:15:44 -04:00
Makefile	IB/rdmavt: Create module framework and handle driver registration	2016-03-10 20:37:04 -05:00