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Subject[PATCH 4.19 62/81] cifs: use cifsInodeInfo->open_file_lock while iterating to avoid a panic
Date
From: Dave Wysochanski <dwysocha@redhat.com>

Commit 487317c99477 ("cifs: add spinlock for the openFileList to
cifsInodeInfo") added cifsInodeInfo->open_file_lock spin_lock to protect
the openFileList, but missed a few places where cifs_inode->openFileList
was enumerated. Change these remaining tcon->open_file_lock to
cifsInodeInfo->open_file_lock to avoid panic in is_size_safe_to_change.

[17313.245641] RIP: 0010:is_size_safe_to_change+0x57/0xb0 [cifs]
[17313.245645] Code: 68 40 48 89 ef e8 19 67 b7 f1 48 8b 43 40 48 8d 4b 40 48 8d 50 f0 48 39 c1 75 0f eb 47 48 8b 42 10 48 8d 50 f0 48 39 c1 74 3a <8b> 80 88 00 00 00 83 c0 01 a8 02 74 e6 48 89 ef c6 07 00 0f 1f 40
[17313.245649] RSP: 0018:ffff94ae1baefa30 EFLAGS: 00010202
[17313.245654] RAX: dead000000000100 RBX: ffff88dc72243300 RCX: ffff88dc72243340
[17313.245657] RDX: dead0000000000f0 RSI: 00000000098f7940 RDI: ffff88dd3102f040
[17313.245659] RBP: ffff88dd3102f040 R08: 0000000000000000 R09: ffff94ae1baefc40
[17313.245661] R10: ffffcdc8bb1c4e80 R11: ffffcdc8b50adb08 R12: 00000000098f7940
[17313.245663] R13: ffff88dc72243300 R14: ffff88dbc8f19600 R15: ffff88dc72243428
[17313.245667] FS: 00007fb145485700(0000) GS:ffff88dd3e000000(0000) knlGS:0000000000000000
[17313.245670] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[17313.245672] CR2: 0000026bb46c6000 CR3: 0000004edb110003 CR4: 00000000007606e0
[17313.245753] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[17313.245756] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[17313.245759] PKRU: 55555554
[17313.245761] Call Trace:
[17313.245803] cifs_fattr_to_inode+0x16b/0x580 [cifs]
[17313.245838] cifs_get_inode_info+0x35c/0xa60 [cifs]
[17313.245852] ? kmem_cache_alloc_trace+0x151/0x1d0
[17313.245885] cifs_open+0x38f/0x990 [cifs]
[17313.245921] ? cifs_revalidate_dentry_attr+0x3e/0x350 [cifs]
[17313.245953] ? cifsFileInfo_get+0x30/0x30 [cifs]
[17313.245960] ? do_dentry_open+0x132/0x330
[17313.245963] do_dentry_open+0x132/0x330
[17313.245969] path_openat+0x573/0x14d0
[17313.245974] do_filp_open+0x93/0x100
[17313.245979] ? __check_object_size+0xa3/0x181
[17313.245986] ? audit_alloc_name+0x7e/0xd0
[17313.245992] do_sys_open+0x184/0x220
[17313.245999] do_syscall_64+0x5b/0x1b0

Fixes: 487317c99477 ("cifs: add spinlock for the openFileList to cifsInodeInfo")

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
fs/cifs/file.c | 27 +++++++++++----------------
1 file changed, 11 insertions(+), 16 deletions(-)

--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1841,13 +1841,12 @@ struct cifsFileInfo *find_readable_file(
{
struct cifsFileInfo *open_file = NULL;
struct cifs_sb_info *cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
- struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);

/* only filter by fsuid on multiuser mounts */
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
fsuid_only = false;

- spin_lock(&tcon->open_file_lock);
+ spin_lock(&cifs_inode->open_file_lock);
/* we could simply get the first_list_entry since write-only entries
are always at the end of the list but since the first entry might
have a close pending, we go through the whole list */
@@ -1859,7 +1858,7 @@ struct cifsFileInfo *find_readable_file(
/* found a good file */
/* lock it so it will not be closed on us */
cifsFileInfo_get(open_file);
- spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_inode->open_file_lock);
return open_file;
} /* else might as well continue, and look for
another, or simply have the caller reopen it
@@ -1867,7 +1866,7 @@ struct cifsFileInfo *find_readable_file(
} else /* write only file */
break; /* write only files are last so must be done */
}
- spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_inode->open_file_lock);
return NULL;
}

@@ -1876,7 +1875,6 @@ struct cifsFileInfo *find_writable_file(
{
struct cifsFileInfo *open_file, *inv_file = NULL;
struct cifs_sb_info *cifs_sb;
- struct cifs_tcon *tcon;
bool any_available = false;
int rc;
unsigned int refind = 0;
@@ -1892,16 +1890,15 @@ struct cifsFileInfo *find_writable_file(
}

cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
- tcon = cifs_sb_master_tcon(cifs_sb);

/* only filter by fsuid on multiuser mounts */
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
fsuid_only = false;

- spin_lock(&tcon->open_file_lock);
+ spin_lock(&cifs_inode->open_file_lock);
refind_writable:
if (refind > MAX_REOPEN_ATT) {
- spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_inode->open_file_lock);
return NULL;
}
list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
@@ -1913,7 +1910,7 @@ refind_writable:
if (!open_file->invalidHandle) {
/* found a good writable file */
cifsFileInfo_get(open_file);
- spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_inode->open_file_lock);
return open_file;
} else {
if (!inv_file)
@@ -1932,7 +1929,7 @@ refind_writable:
cifsFileInfo_get(inv_file);
}

- spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_inode->open_file_lock);

if (inv_file) {
rc = cifs_reopen_file(inv_file, false);
@@ -1946,7 +1943,7 @@ refind_writable:
cifsFileInfo_put(inv_file);
++refind;
inv_file = NULL;
- spin_lock(&tcon->open_file_lock);
+ spin_lock(&cifs_inode->open_file_lock);
goto refind_writable;
}
}
@@ -4007,17 +4004,15 @@ static int cifs_readpage(struct file *fi
static int is_inode_writable(struct cifsInodeInfo *cifs_inode)
{
struct cifsFileInfo *open_file;
- struct cifs_tcon *tcon =
- cifs_sb_master_tcon(CIFS_SB(cifs_inode->vfs_inode.i_sb));

- spin_lock(&tcon->open_file_lock);
+ spin_lock(&cifs_inode->open_file_lock);
list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
- spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_inode->open_file_lock);
return 1;
}
}
- spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_inode->open_file_lock);
return 0;
}


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