This driver wants pxmitpriv->pxmitbuf to be 4-byte aligned. This is ensured by allocating 4 more bytes than required with kmalloc(), then do the p = p + 4 - (p & 3) trick to make sure the pointer is 4-byte aligned. This is unnecessary. Pointers from kmalloc() are already at least 8-byte-aligned. Remove this alignment trick to simplify the code, and also to stop wasting 4 extra bytes of dynamic memory allocator. This also gets rid of a (false) warning from kmemleak. This 4-byte-aligned buffer is used to store pointers from kmalloc(). For 64-bit platforms, pointer size is 8 bytes and kmemleak only scans for pointers in 8-byte blocks, thus it misses the pointers stored in this 4-byte-aligned buffer and thinks that these pointers have been leaked. This is just a false warning, not a real problem. But still, it would be nice to get rid of these warnings. Reported-and-tested-by: syzbot+83763e624cfec6b462cb@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://lore.kernel.org/linux-staging/000000000000809328060a8a4c1c@xxxxxxxxxx Signed-off-by: Nam Cao <namcao@xxxxxxxxxxxxx> --- Patch sent using this driver with this patch applied. drivers/staging/rtl8712/rtl871x_xmit.c | 13 +++++-------- drivers/staging/rtl8712/rtl871x_xmit.h | 1 - 2 files changed, 5 insertions(+), 9 deletions(-) diff --git a/drivers/staging/rtl8712/rtl871x_xmit.c b/drivers/staging/rtl8712/rtl871x_xmit.c index 6353dbe554d3..408616e9afcf 100644 --- a/drivers/staging/rtl8712/rtl871x_xmit.c +++ b/drivers/staging/rtl8712/rtl871x_xmit.c @@ -117,12 +117,9 @@ int _r8712_init_xmit_priv(struct xmit_priv *pxmitpriv, /*init xmit_buf*/ _init_queue(&pxmitpriv->free_xmitbuf_queue); _init_queue(&pxmitpriv->pending_xmitbuf_queue); - pxmitpriv->pallocated_xmitbuf = - kmalloc(NR_XMITBUFF * sizeof(struct xmit_buf) + 4, GFP_ATOMIC); - if (!pxmitpriv->pallocated_xmitbuf) + pxmitpriv->pxmitbuf = kmalloc(NR_XMITBUFF * sizeof(struct xmit_buf), GFP_ATOMIC); + if (!pxmitpriv->pxmitbuf) goto clean_up_frame_buf; - pxmitpriv->pxmitbuf = pxmitpriv->pallocated_xmitbuf + 4 - - ((addr_t)(pxmitpriv->pallocated_xmitbuf) & 3); pxmitbuf = (struct xmit_buf *)pxmitpriv->pxmitbuf; for (i = 0; i < NR_XMITBUFF; i++) { INIT_LIST_HEAD(&pxmitbuf->list); @@ -165,8 +162,8 @@ int _r8712_init_xmit_priv(struct xmit_priv *pxmitpriv, for (k = 0; k < 8; k++) /* delete xmit urb's */ usb_free_urb(pxmitbuf->pxmit_urb[k]); } - kfree(pxmitpriv->pallocated_xmitbuf); - pxmitpriv->pallocated_xmitbuf = NULL; + kfree(pxmitpriv->pxmitbuf); + pxmitpriv->pxmitbuf = NULL; clean_up_frame_buf: kfree(pxmitpriv->pallocated_frame_buf); pxmitpriv->pallocated_frame_buf = NULL; @@ -193,7 +190,7 @@ void _free_xmit_priv(struct xmit_priv *pxmitpriv) pxmitbuf++; } kfree(pxmitpriv->pallocated_frame_buf); - kfree(pxmitpriv->pallocated_xmitbuf); + kfree(pxmitpriv->pxmitbuf); free_hwxmits(padapter); } diff --git a/drivers/staging/rtl8712/rtl871x_xmit.h b/drivers/staging/rtl8712/rtl871x_xmit.h index cdcbc87a3cad..784172c385e3 100644 --- a/drivers/staging/rtl8712/rtl871x_xmit.h +++ b/drivers/staging/rtl8712/rtl871x_xmit.h @@ -244,7 +244,6 @@ struct xmit_priv { int cmdseq; struct __queue free_xmitbuf_queue; struct __queue pending_xmitbuf_queue; - u8 *pallocated_xmitbuf; u8 *pxmitbuf; uint free_xmitbuf_cnt; }; -- 2.39.2
