This is a note to let you know that I've just added the patch titled orangefs: Fix kmemleak in orangefs_prepare_debugfs_help_string() 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: orangefs-fix-kmemleak-in-orangefs_prepare_debugfs_he.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. commit c085d77d80e2f32baf387d9da4a16c8842425809 Author: Zhang Xiaoxu <zhangxiaoxu5@xxxxxxxxxx> Date: Tue Oct 18 12:40:05 2022 +0800 orangefs: Fix kmemleak in orangefs_prepare_debugfs_help_string() [ Upstream commit d23417a5bf3a3afc55de5442eb46e1e60458b0a1 ] When insert and remove the orangefs module, then debug_help_string will be leaked: unreferenced object 0xffff8881652ba000 (size 4096): comm "insmod", pid 1701, jiffies 4294893639 (age 13218.530s) hex dump (first 32 bytes): 43 6c 69 65 6e 74 20 44 65 62 75 67 20 4b 65 79 Client Debug Key 77 6f 72 64 73 20 61 72 65 20 75 6e 6b 6e 6f 77 words are unknow backtrace: [<0000000004e6f8e3>] kmalloc_trace+0x27/0xa0 [<0000000006f75d85>] orangefs_prepare_debugfs_help_string+0x5e/0x480 [orangefs] [<0000000091270a2a>] _sub_I_65535_1+0x57/0xf70 [crc_itu_t] [<000000004b1ee1a3>] do_one_initcall+0x87/0x2a0 [<000000001d0614ae>] do_init_module+0xdf/0x320 [<00000000efef068c>] load_module+0x2f98/0x3330 [<000000006533b44d>] __do_sys_finit_module+0x113/0x1b0 [<00000000a0da6f99>] do_syscall_64+0x35/0x80 [<000000007790b19b>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 When remove the module, should always free debug_help_string. Should always free the allocated buffer when change the free_debug_help_string. Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@xxxxxxxxxx> Signed-off-by: Mike Marshall <hubcap@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c index 7d7df003f9d8..401d70944e49 100644 --- a/fs/orangefs/orangefs-debugfs.c +++ b/fs/orangefs/orangefs-debugfs.c @@ -253,6 +253,8 @@ static int orangefs_kernel_debug_init(void) void orangefs_debugfs_cleanup(void) { debugfs_remove_recursive(debug_dir); + kfree(debug_help_string); + debug_help_string = NULL; } /* open ORANGEFS_KMOD_DEBUG_HELP_FILE */ @@ -706,6 +708,7 @@ int orangefs_prepare_debugfs_help_string(int at_boot) memset(debug_help_string, 0, DEBUG_HELP_STRING_SIZE); strlcat(debug_help_string, new, string_size); mutex_unlock(&orangefs_help_file_lock); + kfree(new); } rc = 0;