There is a deadlock when the reply of FUSE_CANONICAL_PATH from user-
space client, because the kern_path function will issue a new request
and wait the respond from client which has been in wait state. The ba-
cktrace is like this:
<6>[ 518.977731] ntfs-3g S 0 2138 1 0x04000000
<4>[ 518.977745] Call trace:
<4>[ 518.977757] __switch_to+0x130/0x13c
<4>[ 518.977767] __schedule+0x740/0x964
<4>[ 518.977777] schedule+0x70/0x90
<4>[ 518.977794] __fuse_request_send+0x1a0/0x340
<4>[ 518.977808] fuse_simple_request+0x178/0x1c8
<4>[ 518.977818] fuse_lookup_name+0xfc/0x220
<4>[ 518.977829] fuse_lookup+0x48/0x134
<4>[ 518.977842] __lookup_slow+0xc8/0x154
<4>[ 518.977853] walk_component+0x1c0/0x728
<4>[ 518.977863] path_lookupat+0xa8/0x208
<4>[ 518.977875] filename_lookup+0x8c/0x190
<4>[ 518.977887] kern_path+0x30/0x3c
<4>[ 518.977901] fuse_dev_do_write+0x79c/0x114c
<4>[ 518.977914] fuse_dev_write+0x60/0x84
<4>[ 518.977928] do_iter_readv_writev+0x11c/0x158
<4>[ 518.977941] do_iter_write+0x7c/0x1b8
<4>[ 518.977953] vfs_writev+0x84/0xe8
<4>[ 518.977966] do_writev+0x78/0x114
<4>[ 518.977979] __arm64_sys_writev+0x1c/0x24
<4>[ 518.977992] el0_svc_common+0x98/0x160
<4>[ 518.978005] el0_svc_handler+0x5c/0x64
<4>[ 518.978015] el0_svc+0x8/0xc
Fixes: fa199896a3 ("ANDROID: fuse: Add support for d_canonical_path")
Signed-off-by: Cliff Chen <cliff.chen@rock-chips.com>
Change-Id: I13487e5c956c4537c2554a44208d6664653ef4f1
24dace7355