diff --git a/0011-xfs_copy-don-t-use-cached-buffer-reads-until-after-l.patch b/0011-xfs_copy-don-t-use-cached-buffer-reads-until-after-l.patch new file mode 100644 index 0000000000000000000000000000000000000000..be67a26a8f45cc453520586dcca44124afffa97f --- /dev/null +++ b/0011-xfs_copy-don-t-use-cached-buffer-reads-until-after-l.patch @@ -0,0 +1,61 @@ +From baf8a5df8a0c6539818a3f78a68d22648c022e50 Mon Sep 17 00:00:00 2001 +From: "Darrick J. Wong" +Date: Tue, 12 Jul 2022 13:25:33 -0500 +Subject: [PATCH] xfs_copy: don't use cached buffer reads until after + libxfs_mount + +I accidentally tried to xfs_copy an ext4 filesystem, but instead of +rejecting the filesystem, the program instead crashed. I figured out +that zeroing the superblock was enough to trigger this: + +# dd if=/dev/zero of=/dev/sda bs=1024k count=1 +# xfs_copy /dev/sda /dev/sdb +Floating point exception + +The exact crash happens in this line from libxfs_getbuf_flags, which is +called from the main() routine of xfs_copy: + + if (btp == btp->bt_mount->m_ddev_targp) { + (*bpp)->b_pag = xfs_perag_get(btp->bt_mount, + xfs_daddr_to_agno(btp->bt_mount, blkno)); + +The problem here is that the uncached read filled the incore superblock +with zeroes, which means mbuf.sb_agblocks is zero. This causes a +division by zero in xfs_daddr_to_agno, thereby crashing the program. + +In commit f8b581d6, we made it so that xfs_buf structures contain a +passive reference to the associated perag structure. That commit +assumes that no program would try a cached buffer read until the buffer +cache is fully set up, which is true throughout xfsprogs... except for +the beginning of xfs_copy. For whatever reason, it attempts an uncached +read of the superblock to figure out the real superblock size, then +performs a *cached* read with the proper buffer length and verifier. +The cached read crashes the program. + +Fix the problem by changing the (second) cached read into an uncached read. + +Fixes: f8b581d6 ("libxfs: actually make buffers track the per-ag structures") +Signed-off-by: Darrick J. Wong +Reviewed-by: Dave Chinner +Reviewed-by: Christoph Hellwig +Signed-off-by: Eric Sandeen +--- + copy/xfs_copy.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/copy/xfs_copy.c b/copy/xfs_copy.c +index 41f594bd..79f65946 100644 +--- a/copy/xfs_copy.c ++++ b/copy/xfs_copy.c +@@ -748,7 +748,7 @@ main(int argc, char **argv) + /* Do it again, now with proper length and verifier */ + libxfs_buf_relse(sbp); + +- error = -libxfs_buf_read(mbuf.m_ddev_targp, XFS_SB_DADDR, ++ error = -libxfs_buf_read_uncached(mbuf.m_ddev_targp, XFS_SB_DADDR, + 1 << (sb->sb_sectlog - BBSHIFT), 0, &sbp, + &xfs_sb_buf_ops); + if (error) { +-- +2.33.0 + diff --git a/xfsprogs.spec b/xfsprogs.spec index 7a11960699fa5b5d0a31d0c099ad10beda20ae54..5faa62305a7d6300b4c573ea237f609267c56f9e 100644 --- a/xfsprogs.spec +++ b/xfsprogs.spec @@ -1,6 +1,6 @@ Name: xfsprogs Version: 5.14.1 -Release: 13 +Release: 14 Summary: Administration and debugging tools for the XFS file system License: GPL+ and LGPLv2+ URL: https://xfs.wiki.kernel.org @@ -29,6 +29,7 @@ Patch7: 0007-libxcmd-add-return-value-check-for-dynamic-memory-fu.patch Patch8: 0008-xfs_repair-fix-the-problem-of-repair-failure-caused-.patch Patch9: 0009-mkfs.xfs-fix-segmentation-fault-caused-by-accessing-.patch Patch10: 0010-xfs_repair-fix-warn-in-xfs_buf_find-when-growfs-fails.patch +Patch11: 0011-xfs_copy-don-t-use-cached-buffer-reads-until-after-l.patch %description xfsprogs are the userspace utilities that manage XFS filesystems. @@ -112,6 +113,9 @@ rm -rf %{buildroot}%{_datadir}/doc/xfsprogs/ %changelog +* Fri Nov 3 2023 wuguanghao - 5.14.1-14 +- xfs_copy: don't use cached buffer reads until after libxfs_mount + * Tue Sep 12 2023 wuguanghao - 5.14.1-13 - xfs_repair: fix warn in xfs_buf_find when growfs fails