On Wed, Dec 04, 2013 at 01:59:52PM +0100, Paolo Pinto wrote: > Hi list! > > My kernel is compiled with option INVARIANTS and I get a reproducible > kernel panic when trying to read data from a GEOM based compressed > memory disk: > > Unread portion of the kernel message buffer: > panic: bio_length 140288 > cpuid = 3 > KDB: stack backtrace: > #0 0xffffffff80909726 at kdb_backtrace+0x66 > #1 0xffffffff808d0fa8 at panic+0x1d8 > #2 0xffffffff80595949 at mdstart_vnode+0x619
The issue is that geom_uzip creates bios which are larger than MAXPHYS.
As a workaround, the following patch should be enough. It only fires
assert when md really uses pbuf, and since geom_uzip knows nothing
about unmapped bio, the assertion must not trigger.
diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index 8ae51d1..639677e 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -746,12 +746,12 @@ mdstart_vnode(struct md_s *sc, struct bio *bp)
return (error);
}
- KASSERT(bp->bio_length <= MAXPHYS, ("bio_length %jd",
- (uintmax_t)bp->bio_length));
if ((bp->bio_flags & BIO_UNMAPPED) == 0) {
pb = NULL;
aiov.iov_base = bp->bio_data;
} else {
+ KASSERT(bp->bio_length <= MAXPHYS, ("bio_length %jd",
+ (uintmax_t)bp->bio_length));
pb = getpbuf(&md_vnode_pbuf_freecnt);
pmap_qenter((vm_offset_t)pb->b_data, bp->bio_ma, bp->bio_ma_n);
aiov.iov_base = (void *)((vm_offset_t)pb->b_data +
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