From: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com> To: <ath10k@lists.infradead.org> Cc: <mohammed@codeaurora.org>, <linux-wireless@vger.kernel.org>, "Mohammed Shafi Shajakhan" <mohammed@qti.qualcomm.com> Subject: [PATCH] ath10k: Avoid potential page alloc BUG_ON in tx free path Date: Wed, 7 Dec 2016 10:30:32 +0530 [thread overview] Message-ID: <1481086832-17281-1-git-send-email-mohammed@qca.qualcomm.com> (raw) From: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com> 'ath10k_htt_tx_free_cont_txbuf' and 'ath10k_htt_tx_free_cont_frag_desc' have NULL pointer checks to avoid crash if they are called twice but this is as of now not sufficient as these pointers are not assigned to NULL once the contiguous DMA memory allocation is freed, fix this. Though this may not be hit with the explicity check of state variable 'tx_mem_allocated' check, good to have this addressed as well. Below BUG_ON is hit when the above scenario is simulated with kernel debugging enabled page:f6d09a00 count:0 mapcount:-127 mapping: (null) index:0x0 flags: 0x40000000() page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) ------------[ cut here ]------------ kernel BUG at ./include/linux/mm.h:445! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC EIP is at put_page_testzero.part.88+0xd/0xf Call Trace: [<c118a2cc>] __free_pages+0x3c/0x40 [<c118a30e>] free_pages+0x3e/0x50 [<c10222b4>] dma_generic_free_coherent+0x24/0x30 [<f8c1d9a8>] ath10k_htt_tx_free_cont_txbuf+0xf8/0x140 [<f8c1e2a9>] ath10k_htt_tx_destroy+0x29/0xa0 [<f8c143e0>] ath10k_core_destroy+0x60/0x80 [ath10k_core] [<f8acd7e9>] ath10k_pci_remove+0x79/0xa0 [ath10k_pci] [<c13ed7a8>] pci_device_remove+0x38/0xb0 [<c14d3492>] __device_release_driver+0x72/0x100 [<c14d36b7>] driver_detach+0x97/0xa0 [<c14d29c0>] bus_remove_driver+0x40/0x80 [<c14d427a>] driver_unregister+0x2a/0x60 [<c13ec768>] pci_unregister_driver+0x18/0x70 [<f8aced4f>] ath10k_pci_exit+0xd/0x2be [ath10k_pci] [<c1101e78>] SyS_delete_module+0x158/0x210 [<c11b34f1>] ? __might_fault+0x41/0xa0 [<c11b353b>] ? __might_fault+0x8b/0xa0 [<c1001a4b>] do_fast_syscall_32+0x9b/0x1c0 [<c178da34>] sysenter_past_esp+0x45/0x74 Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com> --- drivers/net/wireless/ath/ath10k/htt_tx.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c b/drivers/net/wireless/ath/ath10k/htt_tx.c index 27e49db..86b427f 100644 --- a/drivers/net/wireless/ath/ath10k/htt_tx.c +++ b/drivers/net/wireless/ath/ath10k/htt_tx.c @@ -239,6 +239,7 @@ static void ath10k_htt_tx_free_cont_txbuf(struct ath10k_htt *htt) size = htt->max_num_pending_tx * sizeof(struct ath10k_htt_txbuf); dma_free_coherent(ar->dev, size, htt->txbuf.vaddr, htt->txbuf.paddr); + htt->txbuf.vaddr = NULL; } static int ath10k_htt_tx_alloc_cont_txbuf(struct ath10k_htt *htt) @@ -268,6 +269,7 @@ static void ath10k_htt_tx_free_cont_frag_desc(struct ath10k_htt *htt) size, htt->frag_desc.vaddr, htt->frag_desc.paddr); + htt->frag_desc.vaddr = NULL; } static int ath10k_htt_tx_alloc_cont_frag_desc(struct ath10k_htt *htt) -- 1.9.1
WARNING: multiple messages have this Message-ID (diff)
From: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com> To: ath10k@lists.infradead.org Cc: mohammed@codeaurora.org, linux-wireless@vger.kernel.org, Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com> Subject: [PATCH] ath10k: Avoid potential page alloc BUG_ON in tx free path Date: Wed, 7 Dec 2016 10:30:32 +0530 [thread overview] Message-ID: <1481086832-17281-1-git-send-email-mohammed@qca.qualcomm.com> (raw) From: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com> 'ath10k_htt_tx_free_cont_txbuf' and 'ath10k_htt_tx_free_cont_frag_desc' have NULL pointer checks to avoid crash if they are called twice but this is as of now not sufficient as these pointers are not assigned to NULL once the contiguous DMA memory allocation is freed, fix this. Though this may not be hit with the explicity check of state variable 'tx_mem_allocated' check, good to have this addressed as well. Below BUG_ON is hit when the above scenario is simulated with kernel debugging enabled page:f6d09a00 count:0 mapcount:-127 mapping: (null) index:0x0 flags: 0x40000000() page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) ------------[ cut here ]------------ kernel BUG at ./include/linux/mm.h:445! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC EIP is at put_page_testzero.part.88+0xd/0xf Call Trace: [<c118a2cc>] __free_pages+0x3c/0x40 [<c118a30e>] free_pages+0x3e/0x50 [<c10222b4>] dma_generic_free_coherent+0x24/0x30 [<f8c1d9a8>] ath10k_htt_tx_free_cont_txbuf+0xf8/0x140 [<f8c1e2a9>] ath10k_htt_tx_destroy+0x29/0xa0 [<f8c143e0>] ath10k_core_destroy+0x60/0x80 [ath10k_core] [<f8acd7e9>] ath10k_pci_remove+0x79/0xa0 [ath10k_pci] [<c13ed7a8>] pci_device_remove+0x38/0xb0 [<c14d3492>] __device_release_driver+0x72/0x100 [<c14d36b7>] driver_detach+0x97/0xa0 [<c14d29c0>] bus_remove_driver+0x40/0x80 [<c14d427a>] driver_unregister+0x2a/0x60 [<c13ec768>] pci_unregister_driver+0x18/0x70 [<f8aced4f>] ath10k_pci_exit+0xd/0x2be [ath10k_pci] [<c1101e78>] SyS_delete_module+0x158/0x210 [<c11b34f1>] ? __might_fault+0x41/0xa0 [<c11b353b>] ? __might_fault+0x8b/0xa0 [<c1001a4b>] do_fast_syscall_32+0x9b/0x1c0 [<c178da34>] sysenter_past_esp+0x45/0x74 Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com> --- drivers/net/wireless/ath/ath10k/htt_tx.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c b/drivers/net/wireless/ath/ath10k/htt_tx.c index 27e49db..86b427f 100644 --- a/drivers/net/wireless/ath/ath10k/htt_tx.c +++ b/drivers/net/wireless/ath/ath10k/htt_tx.c @@ -239,6 +239,7 @@ static void ath10k_htt_tx_free_cont_txbuf(struct ath10k_htt *htt) size = htt->max_num_pending_tx * sizeof(struct ath10k_htt_txbuf); dma_free_coherent(ar->dev, size, htt->txbuf.vaddr, htt->txbuf.paddr); + htt->txbuf.vaddr = NULL; } static int ath10k_htt_tx_alloc_cont_txbuf(struct ath10k_htt *htt) @@ -268,6 +269,7 @@ static void ath10k_htt_tx_free_cont_frag_desc(struct ath10k_htt *htt) size, htt->frag_desc.vaddr, htt->frag_desc.paddr); + htt->frag_desc.vaddr = NULL; } static int ath10k_htt_tx_alloc_cont_frag_desc(struct ath10k_htt *htt) -- 1.9.1 _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k
next reply other threads:[~2016-12-07 5:03 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-12-07 5:00 Mohammed Shafi Shajakhan [this message] 2016-12-07 5:00 ` [PATCH] ath10k: Avoid potential page alloc BUG_ON in tx free path Mohammed Shafi Shajakhan 2016-12-15 9:18 ` Kalle Valo 2016-12-15 9:18 ` Kalle Valo
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1481086832-17281-1-git-send-email-mohammed@qca.qualcomm.com \ --to=mohammed@qti.qualcomm.com \ --cc=ath10k@lists.infradead.org \ --cc=linux-wireless@vger.kernel.org \ --cc=mohammed@codeaurora.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.