[4/4] iwlwifi: mvm: fix accessing Null pointer during fw dump collection
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Message ID 1460449011-8417-4-git-send-email-emmanuel.grumbach@intel.com
State Accepted
Delegated to: Kalle Valo
Headers show

Commit Message

Emmanuel Grumbach April 12, 2016, 8:16 a.m. UTC
From: Matti Gottlieb <matti.gottlieb@intel.com>

The firwmare file can come with data that is relevant for paging. This
data is availablet to the firmware upon request, but it stored in the
host's memory. During the firmware init flow, the driver configures the
firmware so that the firwmare knows where is the data.
When paging is used, the variable paging_mem_size is the number of bytes
that are available through paging. This variable is not zeror-ed if the
driver fails to configure the paging in the firmware, but the memory is
freed which is inconsistent.
This inconsistency led to a NULL pointer dereference in the code that
collects the debug data.

Fix this by zero-ing the paging_mem_size variable and NULLify the
relevant pointers, so that the code that collects the debug data will
know that the paging data is not available.

Signed-off-by: Matti Gottlieb <matti.gottlieb@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c | 6 ++++--
 drivers/net/wireless/intel/iwlwifi/mvm/fw.c     | 2 ++
 2 files changed, 6 insertions(+), 2 deletions(-)

Patch
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diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c
index 4856eac..6938cd3 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c
@@ -526,7 +526,8 @@  void iwl_mvm_fw_error_dump(struct iwl_mvm *mvm)
 		file_len += sizeof(*dump_data) + sizeof(*dump_mem) + sram2_len;
 
 	/* Make room for fw's virtual image pages, if it exists */
-	if (mvm->fw->img[mvm->cur_ucode].paging_mem_size)
+	if (mvm->fw->img[mvm->cur_ucode].paging_mem_size &&
+	    mvm->fw_paging_db[0].fw_paging_block)
 		file_len += mvm->num_of_paging_blk *
 			(sizeof(*dump_data) +
 			 sizeof(struct iwl_fw_error_dump_paging) +
@@ -643,7 +644,8 @@  void iwl_mvm_fw_error_dump(struct iwl_mvm *mvm)
 	}
 
 	/* Dump fw's virtual image */
-	if (mvm->fw->img[mvm->cur_ucode].paging_mem_size) {
+	if (mvm->fw->img[mvm->cur_ucode].paging_mem_size &&
+	    mvm->fw_paging_db[0].fw_paging_block) {
 		for (i = 1; i < mvm->num_of_paging_blk + 1; i++) {
 			struct iwl_fw_error_dump_paging *paging;
 			struct page *pages =
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
index 594cd0d..09d895f 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
@@ -144,9 +144,11 @@  void iwl_free_fw_paging(struct iwl_mvm *mvm)
 
 		__free_pages(mvm->fw_paging_db[i].fw_paging_block,
 			     get_order(mvm->fw_paging_db[i].fw_paging_size));
+		mvm->fw_paging_db[i].fw_paging_block = NULL;
 	}
 	kfree(mvm->trans->paging_download_buf);
 	mvm->trans->paging_download_buf = NULL;
+	mvm->trans->paging_db = NULL;
 
 	memset(mvm->fw_paging_db, 0, sizeof(mvm->fw_paging_db));
 }