Author: alc Date: Sat Nov 24 21:52:10 2018 New Revision: 340914 URL: https://svnweb.freebsd.org/changeset/base/340914
Log: blist_meta_alloc assumes that mask=scan->bm_bitmap is nonzero. But if the cursor lies in the middle of the space that the meta node represents, then blanking the low bits of mask may make it zero, and break later code that expects a nonzero value. Add a test that returns failure if the mask has been cleared. Submitted by: Doug Moore <do...@rice.edu> Reported by: pho Tested by: pho X-MFC with: r340402 Differential Revision: https://reviews.freebsd.org/D18058 Modified: head/sys/kern/subr_blist.c Modified: head/sys/kern/subr_blist.c ============================================================================== --- head/sys/kern/subr_blist.c Sat Nov 24 21:23:12 2018 (r340913) +++ head/sys/kern/subr_blist.c Sat Nov 24 21:52:10 2018 (r340914) @@ -764,6 +764,8 @@ blst_meta_alloc(blmeta_t *scan, daddr_t cursor, daddr_ /* Discard any candidates that appear before cursor. */ digit = (cursor / radix) & BLIST_META_MASK; mask &= (u_daddr_t)-1 << digit; + if (mask == 0) + return (SWAPBLK_NONE); /* * If the first try is for a block that includes the cursor, pre-undo _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
