hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAOH1I
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The function cifs_writedata_alloc() first allocates pages and then executes cifs_writedata_direct_alloc(). If the subsequent allocation of wdata fails, the previously allocated pages are not released, leading to a memory leak:
[root@fedora debug]# cat kmemleak unreferenced object 0xff110001287aa000 (size 8192): comm "kworker/u220:9", pid 1604, jiffies 4294753971 (age 19.114s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000c80fa56d>] kmemleak_alloc+0x65/0xd0 [<0000000032ff36c6>] __kmalloc+0x641/0xa50 [<00000000da9a4c31>] cifs_writedata_alloc+0x1d/0x30 [<00000000337073aa>] cifs_writepages+0x3e0/0x1990 [<0000000095bfb1fd>] do_writepages+0x31/0xb0 [<00000000321368a2>] __writeback_single_inode+0x4f/0x550 [<00000000f200b315>] writeback_sb_inodes+0x24a/0x7a0 [<00000000badd6d82>] __writeback_inodes_wb+0x88/0x120 [<000000000632fc4a>] wb_writeback+0x3aa/0x4c0 [<00000000c184a6e4>] wb_workfn+0x507/0x770 [<000000005d8f6f94>] process_one_work+0x226/0x540 [<000000000c3dd58a>] worker_thread+0x1b3/0x680 [<00000000457537ac>] kthread+0x159/0x1c0 [<000000000ef58c85>] ret_from_fork+0x1f/0x30
This issue can be avoided by promptly using kvfree.
Fixes: 8e7360f67e75 ("CIFS: Add support for direct pages in wdata") Signed-off-by: Zizhi Wo wozizhi@huawei.com --- fs/cifs/cifssmb.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index cb70f0c6aa1b..15b039820a26 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -2109,12 +2109,17 @@ cifs_writev_complete(struct work_struct *work) struct cifs_writedata * cifs_writedata_alloc(unsigned int nr_pages, work_func_t complete) { + struct cifs_writedata *wdata = NULL; + struct page **pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); - if (pages) - return cifs_writedata_direct_alloc(pages, complete); + if (pages) { + wdata = cifs_writedata_direct_alloc(pages, complete); + if (!wdata) + kvfree(pages); + }
- return NULL; + return wdata; }
struct cifs_writedata *