From: Dave Chinner Date: Wed, 18 Mar 2015 04:10:09 +0000 (+1100) Subject: repair: superblock buffers need to be sector sized X-Git-Tag: v3.2.3-rc1~25 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8bc43a39facea94cc276df86956f4e6bf1ad05f6;p=thirdparty%2Fxfsprogs-dev.git repair: superblock buffers need to be sector sized In secondary_sb_wack() we zero the unused portion of both the on-disk superblock and the in-memory copy that we have. When the device sector size is 4k, this causes xfs_repair to crash like so: # xfs_repair /dev/ram1 Phase 1 - find and verify superblock... Phase 2 - using internal log - zero log... - scan filesystem freespace and inode maps... bad magic number bad on-disk superblock 3 - bad magic number primary/secondary superblock 3 conflict - AG superblock geometry info conflicts with filesystem geometry zeroing unused portion of secondary superblock (AG #3) # The stack trace is indicative: #0 memset () #1 0x000000000040404b in secondary_sb_wack #2 verify_set_agheader #3 0x0000000000427b4b in scan_ag #4 0x000000000042a2ca in worker_thread #5 0x00007ffff77ba0a4 in start_thread #6 0x00007ffff74efc2d in clone Which points at memset overrunning the in memory buffer, as it is only 512 bytes in length. Signed-off-by: Dave Chinner Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- diff --git a/repair/scan.c b/repair/scan.c index ce8d7f5f8..12aa782e1 100644 --- a/repair/scan.c +++ b/repair/scan.c @@ -1485,7 +1485,7 @@ scan_ag( int status; char *objname = NULL; - sb = (struct xfs_sb *)calloc(BBSIZE, 1); + sb = (struct xfs_sb *)calloc(BBTOB(XFS_FSS_TO_BB(mp, 1)), 1); if (!sb) { do_error(_("can't allocate memory for superblock\n")); return;