This is a note to let you know that I've just added the patch titled iwlwifi: mvm: writing zero bytes to debugfs causes a crash to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: iwlwifi-mvm-writing-zero-bytes-to-debugfs-causes-a-crash.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 251fe09f13bfb54c1ede66ee8bf8ddd0061c4f7c Mon Sep 17 00:00:00 2001 From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Thu, 23 Mar 2017 13:40:00 +0300 Subject: iwlwifi: mvm: writing zero bytes to debugfs causes a crash From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> commit 251fe09f13bfb54c1ede66ee8bf8ddd0061c4f7c upstream. This is a static analysis fix. The warning is: drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c:912 iwl_mvm_fw_dbg_collect() warn: integer overflows 'sizeof(*desc) + len' I guess this code is supposed to take a NUL character, but if we write zero bytes then it tries to write -1 characters and crashes. Fixes: c91b865cb14d ("iwlwifi: mvm: support description for user triggered fw dbg collection") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c @@ -1056,6 +1056,8 @@ static ssize_t iwl_dbgfs_fw_dbg_collect_ if (ret) return ret; + if (count == 0) + return 0; iwl_mvm_fw_dbg_collect(mvm, FW_DBG_TRIGGER_USER, buf, (count - 1), NULL); Patches currently in stable-queue which might be from dan.carpenter@xxxxxxxxxx are queue-4.9/scsi-scsi_dh_emc-return-success-in-clariion_std_inquiry.patch queue-4.9/iwlwifi-mvm-writing-zero-bytes-to-debugfs-causes-a-crash.patch