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wifi: brcmfmac: make release_scratchbuffers idempotent

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brcmf_pcie_release_scratchbuffers() frees the shared.scratch and
shared.ringupd DMA buffers with dma_free_coherent() but does not clear
the pointers afterwards, unlike the sibling release_ringbuffers() which
NULLs commonrings/flowrings/idxbuf on release.

Both the bus_reset .reset callback (brcmf_pcie_reset) and
brcmf_pcie_remove() call release_scratchbuffers.  When reset teardown
has run before removal, remove's own teardown would call
dma_free_coherent() a second time on the already-freed DMA allocation.

NULL the pointers after free, matching release_ringbuffers(), so a later
release observes that the allocation has already been released.  This
patch makes repeated sequential release safe; the reset-work lifetime is
handled separately by the following patch.

This issue was found by an in-house static analysis tool.

Fixes: 4684997d9e ("brcmfmac: reset PCIe bus on a firmware crash")
Cc: stable@vger.kernel.org
Signed-off-by: Fan Wu <fanwu01@zju.edu.cn>
Assisted-by: Codex:gpt-5.6
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Link: https://patch.msgid.link/20260718024353.3147201-2-fanwu01@zju.edu.cn
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Fan Wu 2026-07-18 02:43:52 +00:00 committed by Johannes Berg
parent a007a384c9
commit 538c51e9d1
1 changed files with 6 additions and 2 deletions
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8
drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
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@ -1383,16 +1383,20 @@ static int brcmf_pcie_init_ringbuffers(struct brcmf_pciedev_info *devinfo)
static void
brcmf_pcie_release_scratchbuffers(struct brcmf_pciedev_info *devinfo)
{
if (devinfo->shared.scratch)
if (devinfo->shared.scratch) {
dma_free_coherent(&devinfo->pdev->dev,
BRCMF_DMA_D2H_SCRATCH_BUF_LEN,
devinfo->shared.scratch,
devinfo->shared.scratch_dmahandle);
if (devinfo->shared.ringupd)
devinfo->shared.scratch = NULL;
}
if (devinfo->shared.ringupd) {
dma_free_coherent(&devinfo->pdev->dev,
BRCMF_DMA_D2H_RINGUPD_BUF_LEN,
devinfo->shared.ringupd,
devinfo->shared.ringupd_dmahandle);
devinfo->shared.ringupd = NULL;
}
}
static int brcmf_pcie_init_scratchbuffers(struct brcmf_pciedev_info *devinfo)