[PATCH 3/3] cifs: Fix memory allocation in __smb2_handle_cancelled_cmd()

[Tim Gardner]

From: "Paulo Alcantara (SUSE)" <pc at cjr.nz>

BugLink: https://bugs.launchpad.net/bugs/1918714

__smb2_handle_cancelled_cmd() is called under a spin lock held in
cifs_mid_q_entry_release(), so make its memory allocation GFP_ATOMIC.

This issue was observed when running xfstests generic/028:

[ 1722.589204] CIFS VFS: \\192.168.30.26 Cancelling wait for mid 72064 cmd: 5
[ 1722.590687] CIFS VFS: \\192.168.30.26 Cancelling wait for mid 72065 cmd: 17
[ 1722.593529] CIFS VFS: \\192.168.30.26 Cancelling wait for mid 72066 cmd: 6
[ 1723.039014] BUG: sleeping function called from invalid context at mm/slab.h:565
[ 1723.040710] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 30877, name: cifsd
[ 1723.045098] CPU: 3 PID: 30877 Comm: cifsd Not tainted 5.5.0-rc4+ #313
[ 1723.046256] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
[ 1723.048221] Call Trace:
[ 1723.048689]  dump_stack+0x97/0xe0
[ 1723.049268]  ___might_sleep.cold+0xd1/0xe1
[ 1723.050069]  kmem_cache_alloc_trace+0x204/0x2b0
[ 1723.051051]  __smb2_handle_cancelled_cmd+0x40/0x140 [cifs]
[ 1723.052137]  smb2_handle_cancelled_mid+0xf6/0x120 [cifs]
[ 1723.053247]  cifs_mid_q_entry_release+0x44d/0x630 [cifs]
[ 1723.054351]  ? cifs_reconnect+0x26a/0x1620 [cifs]
[ 1723.055325]  cifs_demultiplex_thread+0xad4/0x14a0 [cifs]
[ 1723.056458]  ? cifs_handle_standard+0x2c0/0x2c0 [cifs]
[ 1723.057365]  ? kvm_sched_clock_read+0x14/0x30
[ 1723.058197]  ? sched_clock+0x5/0x10
[ 1723.058838]  ? sched_clock_cpu+0x18/0x110
[ 1723.059629]  ? lockdep_hardirqs_on+0x17d/0x250
[ 1723.060456]  kthread+0x1ab/0x200
[ 1723.061149]  ? cifs_handle_standard+0x2c0/0x2c0 [cifs]
[ 1723.062078]  ? kthread_create_on_node+0xd0/0xd0
[ 1723.062897]  ret_from_fork+0x3a/0x50

Signed-off-by: Paulo Alcantara (SUSE) <pc at cjr.nz>
Fixes: 9150c3adbf24 ("CIFS: Close open handle after interrupted close")
Cc: Stable <stable at vger.kernel.org>
Signed-off-by: Steve French <stfrench at microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov at microsoft.com>
(cherry picked from commit 0a5a98863c9debc02387b3d23c46d187756f5e2b)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 fs/cifs/smb2misc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index d15ace6151d9..c3a6125ff9cc 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -681,7 +681,7 @@ __smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid,
 {
 	struct close_cancelled_open *cancelled;
 
-	cancelled = kzalloc(sizeof(*cancelled), GFP_KERNEL);
+	cancelled = kzalloc(sizeof(*cancelled), GFP_ATOMIC);
 	if (!cancelled)
 		return -ENOMEM;
 
-- 
2.17.1