3.16.70-rc1 review patch. If anyone has any objections, please let me know.
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From: Jack Morgenstein jackm@dev.mellanox.co.il
commit 8511a653e9250ef36b95803c375a7be0e2edb628 upstream.
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: c82e9aa0a8bc ("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: Ben Hutchings ben@decadent.org.uk --- drivers/net/ethernet/mellanox/mlx4/resource_tracker.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c +++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c @@ -2460,13 +2460,13 @@ static int qp_get_mtt_size(struct mlx4_q int total_pages; int total_mem; int page_offset = (be32_to_cpu(qpc->params2) >> 6) & 0x3f; + int tot;
sq_size = 1 << (log_sq_size + log_sq_sride + 4); rq_size = (srq|rss|xrc) ? 0 : (1 << (log_rq_size + log_rq_stride + 4)); total_mem = sq_size + rq_size; - total_pages = - roundup_pow_of_two((total_mem + (page_offset << 6)) >> - page_shift); + tot = (total_mem + (page_offset << 6)) >> page_shift; + total_pages = !tot ? 1 : roundup_pow_of_two(tot);
return total_pages; }