patches for DPDK stable branches
 help / color / mirror / Atom feed
* [dpdk-stable] [PATCH] net/mlx5: fix left shift extension of doorbell bitmap
@ 2020-05-15  8:13 Bing Zhao
  2020-05-17  5:45 ` Matan Azrad
  2020-05-17  9:18 ` Raslan Darawsheh
  0 siblings, 2 replies; 4+ messages in thread
From: Bing Zhao @ 2020-05-15  8:13 UTC (permalink / raw)
  To: viacheslavo, rasland; +Cc: orika, matan, dev, stable, dekelp

The doorbell record is organized with page and bitmap. When some new
doorbell needs to be associated with a queue, the bit will be set
in the bitmap to indicate the corresponding doorbell occupied. A
counter is used to record the number of doorbell occupied to speed
up the searching.
If the number reachs the maximal value of a pre-defined number of a
page, a new page will be allocated. If not, then the bitmap will be
checked to find a free one.
The LSHIFT and OR (AND NOT) operations are used to update the bitmap
of a page. But 1 will be treated as a signed integer when compiling.
When the shift number is 31, the shifted value will be considered as
negative. Then a wrong extension will be done when setting it to a
64-bits variable. All the upper 32-bits will be set to 1 by such
extension.
Then a wrong offset value will be calculated because of this. The
next 64 bits will be also treated as the bitmap and get corrupted
through the bit set operation.
The immediate value 1 needs to be used as 64 bits width explicitly.

Fixes: 21cae8580fd0 ("net/mlx5: allocate door-bells via DevX")
Cc: dekelp@mellanox.com
Cc: stable@dpdk.org

Signed-off-by: Bing Zhao <bingz@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
---
 drivers/net/mlx5/mlx5.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c
index 1445809..ab4adec 100644
--- a/drivers/net/mlx5/mlx5.c
+++ b/drivers/net/mlx5/mlx5.c
@@ -2174,7 +2174,7 @@ struct mlx5_flow_id_pool *
 	/* Find the first clear bit. */
 	MLX5_ASSERT(i < MLX5_DBR_BITMAP_SIZE);
 	j = rte_bsf64(~page->dbr_bitmap[i]);
-	page->dbr_bitmap[i] |= (1 << j);
+	page->dbr_bitmap[i] |= (UINT64_C(1) << j);
 	page->dbr_count++;
 	*dbr_page = page;
 	return (((i * 64) + j) * sizeof(uint64_t));
@@ -2219,7 +2219,7 @@ struct mlx5_flow_id_pool *
 		int i = offset / 64;
 		int j = offset % 64;
 
-		page->dbr_bitmap[i] &= ~(1 << j);
+		page->dbr_bitmap[i] &= ~(UINT64_C(1) << j);
 	}
 	return ret;
 }
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-05-17  9:54 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-15  8:13 [dpdk-stable] [PATCH] net/mlx5: fix left shift extension of doorbell bitmap Bing Zhao
2020-05-17  5:45 ` Matan Azrad
2020-05-17  9:18 ` Raslan Darawsheh
2020-05-17  9:54   ` Raslan Darawsheh

patches for DPDK stable branches

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/stable/0 stable/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 stable stable/ https://inbox.dpdk.org/stable \
		stable@dpdk.org
	public-inbox-index stable

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.stable


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git