Re: [syzbot] memory leak in __get_metapage

[Fabio M. De Francesco]

On Tuesday, October 4, 2022 10:49:42 AM CEST syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    4fe89d07dcc2 Linux 6.0
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=169a7924880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=21254cf9c7c084e0
> dashboard link: https://syzkaller.appspot.com/bug?extid=389b82b29093b3e2640a
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils 
for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10bdd7ec880000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/651a252f7035/
disk-4fe89d07.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/776feb8e0e5b/
vmlinux-4fe89d07.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+389b82b29093b3e2640a@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> BUG: memory leak
> unreferenced object 0xffff888114339e80 (size 128):
>   comm "syz-executor.0", pid 3673, jiffies 4295017005 (age 12.610s)
>   hex dump (first 32 bytes):
>     00 10 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:
>     [<ffffffff814927b3>] mempool_alloc+0x73/0x230 mm/mempool.c:392
>     [<ffffffff81c5aefa>] alloc_metapage fs/jfs/jfs_metapage.c:176 [inline]
>     [<ffffffff81c5aefa>] __get_metapage+0x38a/0x9b0 fs/jfs/jfs_metapage.c:651
>     [<ffffffff81c43862>] diNewExt+0x3f2/0x9d0 fs/jfs/jfs_imap.c:2265
>     [<ffffffff81c45254>] diAllocExt fs/jfs/jfs_imap.c:1945 [inline]
>     [<ffffffff81c45254>] diAllocAG+0x9a4/0xd50 fs/jfs/jfs_imap.c:1662
>     [<ffffffff81c4707f>] diAlloc+0x31f/0x900 fs/jfs/jfs_imap.c:1583
>     [<ffffffff81c57d9a>] ialloc+0x6a/0x3a0 fs/jfs/jfs_inode.c:56
>     [<ffffffff81c3a4c7>] jfs_mkdir+0xf7/0x480 fs/jfs/namei.c:225
>     [<ffffffff815fc703>] vfs_mkdir+0x223/0x340 fs/namei.c:4013
>     [<ffffffff816056e5>] do_mkdirat+0x1a5/0x1e0 fs/namei.c:4038
>     [<ffffffff81605859>] __do_sys_mkdir fs/namei.c:4058 [inline]
>     [<ffffffff81605859>] __se_sys_mkdir fs/namei.c:4056 [inline]
>     [<ffffffff81605859>] __x64_sys_mkdir+0x69/0x90 fs/namei.c:4056
>     [<ffffffff845eab95>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>     [<ffffffff845eab95>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>     [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> BUG: memory leak
> unreferenced object 0xffff888114339e00 (size 128):
>   comm "syz-executor.0", pid 3673, jiffies 4295017005 (age 12.610s)
>   hex dump (first 32 bytes):
>     00 10 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:
>     [<ffffffff814927b3>] mempool_alloc+0x73/0x230 mm/mempool.c:392
>     [<ffffffff81c5aefa>] alloc_metapage fs/jfs/jfs_metapage.c:176 [inline]
>     [<ffffffff81c5aefa>] __get_metapage+0x38a/0x9b0 fs/jfs/jfs_metapage.c:651
>     [<ffffffff81c43862>] diNewExt+0x3f2/0x9d0 fs/jfs/jfs_imap.c:2265
>     [<ffffffff81c45254>] diAllocExt fs/jfs/jfs_imap.c:1945 [inline]
>     [<ffffffff81c45254>] diAllocAG+0x9a4/0xd50 fs/jfs/jfs_imap.c:1662
>     [<ffffffff81c4707f>] diAlloc+0x31f/0x900 fs/jfs/jfs_imap.c:1583
>     [<ffffffff81c57d9a>] ialloc+0x6a/0x3a0 fs/jfs/jfs_inode.c:56
>     [<ffffffff81c3a4c7>] jfs_mkdir+0xf7/0x480 fs/jfs/namei.c:225
>     [<ffffffff815fc703>] vfs_mkdir+0x223/0x340 fs/namei.c:4013
>     [<ffffffff816056e5>] do_mkdirat+0x1a5/0x1e0 fs/namei.c:4038
>     [<ffffffff81605859>] __do_sys_mkdir fs/namei.c:4058 [inline]
>     [<ffffffff81605859>] __se_sys_mkdir fs/namei.c:4056 [inline]
>     [<ffffffff81605859>] __x64_sys_mkdir+0x69/0x90 fs/namei.c:4056
>     [<ffffffff845eab95>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>     [<ffffffff845eab95>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>     [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> BUG: memory leak
> unreferenced object 0xffff888114339d80 (size 128):
>   comm "syz-executor.0", pid 3673, jiffies 4295017005 (age 12.610s)
>   hex dump (first 32 bytes):
>     00 10 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:
>     [<ffffffff814927b3>] mempool_alloc+0x73/0x230 mm/mempool.c:392
>     [<ffffffff81c5aefa>] alloc_metapage fs/jfs/jfs_metapage.c:176 [inline]
>     [<ffffffff81c5aefa>] __get_metapage+0x38a/0x9b0 fs/jfs/jfs_metapage.c:651
>     [<ffffffff81c43862>] diNewExt+0x3f2/0x9d0 fs/jfs/jfs_imap.c:2265
>     [<ffffffff81c45254>] diAllocExt fs/jfs/jfs_imap.c:1945 [inline]
>     [<ffffffff81c45254>] diAllocAG+0x9a4/0xd50 fs/jfs/jfs_imap.c:1662
>     [<ffffffff81c4707f>] diAlloc+0x31f/0x900 fs/jfs/jfs_imap.c:1583
>     [<ffffffff81c57d9a>] ialloc+0x6a/0x3a0 fs/jfs/jfs_inode.c:56
>     [<ffffffff81c3a4c7>] jfs_mkdir+0xf7/0x480 fs/jfs/namei.c:225
>     [<ffffffff815fc703>] vfs_mkdir+0x223/0x340 fs/namei.c:4013
>     [<ffffffff816056e5>] do_mkdirat+0x1a5/0x1e0 fs/namei.c:4038
>     [<ffffffff81605859>] __do_sys_mkdir fs/namei.c:4058 [inline]
>     [<ffffffff81605859>] __se_sys_mkdir fs/namei.c:4056 [inline]
>     [<ffffffff81605859>] __x64_sys_mkdir+0x69/0x90 fs/namei.c:4056
>     [<ffffffff845eab95>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>     [<ffffffff845eab95>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>     [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> BUG: memory leak
> unreferenced object 0xffff8881142f0300 (size 128):
>   comm "syz-executor.0", pid 3676, jiffies 4295017533 (age 7.330s)
>   hex dump (first 32 bytes):
>     00 10 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:
>     [<ffffffff814927b3>] mempool_alloc+0x73/0x230 mm/mempool.c:392
>     [<ffffffff81c5aefa>] alloc_metapage fs/jfs/jfs_metapage.c:176 [inline]
>     [<ffffffff81c5aefa>] __get_metapage+0x38a/0x9b0 fs/jfs/jfs_metapage.c:651
>     [<ffffffff81c43862>] diNewExt+0x3f2/0x9d0 fs/jfs/jfs_imap.c:2265
>     [<ffffffff81c45254>] diAllocExt fs/jfs/jfs_imap.c:1945 [inline]
>     [<ffffffff81c45254>] diAllocAG+0x9a4/0xd50 fs/jfs/jfs_imap.c:1662
>     [<ffffffff81c4707f>] diAlloc+0x31f/0x900 fs/jfs/jfs_imap.c:1583
>     [<ffffffff81c57d9a>] ialloc+0x6a/0x3a0 fs/jfs/jfs_inode.c:56
>     [<ffffffff81c3a4c7>] jfs_mkdir+0xf7/0x480 fs/jfs/namei.c:225
>     [<ffffffff815fc703>] vfs_mkdir+0x223/0x340 fs/namei.c:4013
>     [<ffffffff816056e5>] do_mkdirat+0x1a5/0x1e0 fs/namei.c:4038
>     [<ffffffff81605859>] __do_sys_mkdir fs/namei.c:4058 [inline]
>     [<ffffffff81605859>] __se_sys_mkdir fs/namei.c:4056 [inline]
>     [<ffffffff81605859>] __x64_sys_mkdir+0x69/0x90 fs/namei.c:4056
>     [<ffffffff845eab95>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>     [<ffffffff845eab95>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>     [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 2e8461ce74de..b3ba1cefc230 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -678,6 +678,7 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 
 unlock:
 	unlock_page(page);
+	put_page(page);
 	return NULL;
 }