Re: kern/51129 (Disconnecting USB SD card without umount causes file operations to hang)

[coypu%sdf.org@localhost]

The following reply was made to PR kern/51129; it has been noted by GNATS.

From: coypu%sdf.org@localhost
To: gnats-bugs%NetBSD.org@localhost
Cc: jdolecek%NetBSD.org@localhost
Subject: Re: kern/51129 (Disconnecting USB SD card without umount causes file
 operations to hang)
Date: Thu, 20 Apr 2017 17:34:49 +0000

 Plug USB
 mount
 disconnect, reconnect USB
 umount
 
 660      1 3  10         0   fffffe8475baaaa0             umount biowait
 crash> bt/a fffffe8475baaaa0
 trace: pid 660 lid 1 at 0xfffffe811d942880
 sleepq_block() at sleepq_block+0x97
 cv_wait() at cv_wait+0x9e
 biowait() at biowait+0x42
 bread() at bread+0x2e
 ffs_init_vnode() at ffs_init_vnode+0xa7
 ffs_loadvnode() at ffs_loadvnode+0x43
 vcache_get() at vcache_get+0x293
 ufs_vget() at ufs_vget+0x23
 ufs_root() at ufs_root+0x1c
 VFS_ROOT() at VFS_ROOT+0x1c
 lookup_once() at lookup_once+0x250
 namei_tryemulroot.constprop.9() at namei_tryemulroot.constprop.9+0x3a9
 namei() at namei+0x43
 fd_nameiat.isra.2() at fd_nameiat.isra.2+0x54
 do_sys_statat() at do_sys_statat+0x77
 sys___lstat50() at sys___lstat50+0x25
 syscall() at syscall+0x1bc
 --- syscall (number 441) ---
 785bb70ae67a:
 
 
 Idea that may not be sensible: using cv_timedwait instead in biowait and
 setting an error on EWOULDBLOCK.
 
 Alternatively using this time to cv_broadcast failures (???)
 umass0: BBB reset failed, TIMEOUT
 umass0: BBB bulk-in clear stall failed, TIMEOUT
 umass0: BBB bulk-out clear stall failed, TIMEOUT