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author | trasz <trasz@FreeBSD.org> | 2015-10-18 14:34:13 +0000 |
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committer | trasz <trasz@FreeBSD.org> | 2015-10-18 14:34:13 +0000 |
commit | 43f70df8998af40bd659a3123e2ea855d798c4c4 (patch) | |
tree | ef386a207a76d5a8d6ce74e375ab104b07fb2ae5 | |
parent | 2f6e19044af1dd669f4e0a638b251f9104874f02 (diff) | |
download | FreeBSD-src-43f70df8998af40bd659a3123e2ea855d798c4c4.zip FreeBSD-src-43f70df8998af40bd659a3123e2ea855d798c4c4.tar.gz |
MFC r286237:
Fix panic that would happen on forcibly unmounting devfs (note that
as it is now, devfs ignores MNT_FORCE anyway, so it needs to be modified
to trigger the panic) with consumers still opened.
Note that this still results in a leak of r/w/e counters. It seems
to be harmless, though. If anyone knows a better way to approach
this - please tell.
Sponsored by: The FreeBSD Foundation
-rw-r--r-- | sys/geom/geom_dev.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/sys/geom/geom_dev.c b/sys/geom/geom_dev.c index 621a037..bf2ba9e 100644 --- a/sys/geom/geom_dev.c +++ b/sys/geom/geom_dev.c @@ -399,6 +399,20 @@ g_dev_close(struct cdev *dev, int flags, int fmt, struct thread *td) #else e = 0; #endif + + /* + * The vgonel(9) - caused by eg. forced unmount of devfs - calls + * VOP_CLOSE(9) on devfs vnode without any FREAD or FWRITE flags, + * which would result in zero deltas, which in turn would cause + * panic in g_access(9). + * + * Note that we cannot zero the counters (ie. do "r = cp->acr" + * etc) instead, because the consumer might be opened in another + * devfs instance. + */ + if (r + w + e == 0) + return (EINVAL); + sc = cp->private; mtx_lock(&sc->sc_mtx); sc->sc_open += r + w + e; |