Commit f1678a4c authored Dec 06, 2017 by Serge Semin Committed by Jon Mason Jan 28, 2018

NTB: Fix UB/bug in ntb_mw_get_align()



Simple (1 << pidx) operation causes undefined behaviour when
pidx >= 32. It must be casted to u64 to match the actual return
value of ntb_link_is_up() method, so to have all the possible
peer indexes covered and to get rid of undefined behaviour.
Additionally there are special macros in "linux/bitops.h" to perform
the bit-set-shift operations, so it's recommended to have them used
for proper bit setting.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

parent 417cf39c

include/linux/ntb.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -767,7 +767,7 @@ static inline int ntb_mw_get_align(struct ntb_dev *ntb, int pidx, int widx,
		resource_size_t *size_align,
		resource_size_t *size_max)
		{
		if (!(ntb_link_is_up(ntb, NULL, NULL) & (1 << pidx)))
		if (!(ntb_link_is_up(ntb, NULL, NULL) & BIT_ULL(pidx)))
		return -ENOTCONN;

		return ntb->ops->mw_get_align(ntb, pidx, widx, addr_align, size_align,

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