We encountered a segfault while testing the mkfs.xfs + iscsi.
(gdb) bt
#0 libxfs_log_sb (tp=0xaaaafaea0630) at xfs_sb.c:810
#1 0x0000aaaaca991468 in __xfs_trans_commit (tp=<optimized out>, tp@entry=0xaaaafaea0630, regrant=regrant@entry=true) at trans.c:995
#2 0x0000aaaaca991790 in libxfs_trans_roll (tpp=tpp@entry=0xfffffe1f3018) at trans.c:103
#3 0x0000aaaaca9bcde8 in xfs_dialloc_roll (agibp=0xaaaafaea2fa0, tpp=0xfffffe1f31c8) at xfs_ialloc.c:1561
#4 xfs_dialloc_try_ag (ok_alloc=true, new_ino=<synthetic pointer>, parent=0, pag=0xaaaafaea0210, tpp=0xfffffe1f31c8) at xfs_ialloc.c:1698
#5 xfs_dialloc (tpp=tpp@entry=0xfffffe1f31c8, parent=0, mode=mode@entry=16877, new_ino=new_ino@entry=0xfffffe1f3128) at xfs_ialloc.c:1776
#6 0x0000aaaaca9925b0 in libxfs_dir_ialloc (tpp=tpp@entry=0xfffffe1f31c8, dp=dp@entry=0x0, mode=mode@entry=16877, nlink=nlink@entry=1, rdev=rdev@entry=0, cr=cr@entry=0xfffffe1f31d0,
fsx=fsx@entry=0xfffffe1f36a4, ipp=ipp@entry=0xfffffe1f31c0) at util.c:525
#7 0x0000aaaaca988fac in parseproto (mp=0xfffffe1f36c8, pip=0x0, fsxp=0xfffffe1f36a4, pp=0xfffffe1f3370, name=0x0) at proto.c:552
#8 0x0000aaaaca9867a4 in main (argc=<optimized out>, argv=<optimized out>) at xfs_mkfs.c:4217
(gdb) p bp
$1 = 0x0
```
void
xfs_log_sb(
struct xfs_trans *tp)
{
// iscsi offline
...
// failed to read sb, bp = NULL
struct xfs_buf *bp = xfs_trans_getsb(tp);
...
}
```
When writing data to sb, if the device is abnormal at this time,
the bp may be empty. Using it without checking will result in
a segfault.
So before using it, we need to check if the bp is empty and return
the error.
Signed-off-by: Wu Guanghao <wuguanghao3@xxxxxxxxxx>
---
libxfs/trans.c | 4 +++-
libxfs/xfs_attr_leaf.c | 2 +-
libxfs/xfs_bmap.c | 7 +++++--
libxfs/xfs_sb.c | 23 ++++++++++++++++++++---
libxfs/xfs_sb.h | 2 +-
mkfs/proto.c | 15 ++++++++++++---
6 files changed, 42 insertions(+), 11 deletions(-)
diff --git a/libxfs/trans.c b/libxfs/trans.c
index 553f9471..b37e92d2 100644
--- a/libxfs/trans.c
+++ b/libxfs/trans.c
@@ -992,7 +992,9 @@ __xfs_trans_commit(
sbp->sb_fdblocks += tp->t_fdblocks_delta;
if (tp->t_frextents_delta)
sbp->sb_frextents += tp->t_frextents_delta;
- xfs_log_sb(tp);
+ error = xfs_log_sb(tp);
+ if (error)
+ goto out_unreserve;
}
trans_committed(tp);
diff --git a/libxfs/xfs_attr_leaf.c b/libxfs/xfs_attr_leaf.c
index 6cac2531..73079df1 100644
--- a/libxfs/xfs_attr_leaf.c
+++ b/libxfs/xfs_attr_leaf.c
@@ -668,7 +668,7 @@ xfs_sbversion_add_attr2(
spin_lock(&mp->m_sb_lock);
xfs_add_attr2(mp);
spin_unlock(&mp->m_sb_lock);
- xfs_log_sb(tp);
+ ASSERT(!xfs_log_sb(tp));
}
/*
diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c
index 76591d07..63c3cf7f 100644
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -1053,8 +1053,11 @@ xfs_bmap_add_attrfork(
log_sb = true;
}
spin_unlock(&mp->m_sb_lock);
- if (log_sb)
- xfs_log_sb(tp);
+ if (log_sb) {
+ error = xfs_log_sb(tp);
+ if (error)
+ goto trans_cancel;
+ }
}
error = xfs_trans_commit(tp);
diff --git a/libxfs/xfs_sb.c b/libxfs/xfs_sb.c
index 64b4e7be..21611427 100644
--- a/libxfs/xfs_sb.c
+++ b/libxfs/xfs_sb.c
@@ -949,13 +949,15 @@ xfs_sb_mount_common(
* level of locking that is needed to protect the in-core superblock from
* concurrent access.
*/
-void
+int
xfs_log_sb(
struct xfs_trans *tp)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_buf *bp = xfs_trans_getsb(tp);
+ if (!bp)
+ return -EIO;
/*
* Lazy sb counters don't update the in-core superblock so do that now.
* If this is at unmount, the counters will be exactly correct, but at
@@ -980,6 +982,8 @@ xfs_log_sb(
xfs_sb_to_disk(bp->b_addr, &mp->m_sb);
xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SB_BUF);
xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsb) - 1);
+
+ return 0;
}
/*
@@ -1006,7 +1010,12 @@ xfs_sync_sb(
if (error)
return error;
- xfs_log_sb(tp);
+ error = xfs_log_sb(tp);
+ if (error) {
+ xfs_trans_cancel(tp);
+ return error;
+ }
+
if (wait)
xfs_trans_set_sync(tp);
return xfs_trans_commit(tp);
@@ -1103,7 +1112,15 @@ xfs_sync_sb_buf(
return error;
bp = xfs_trans_getsb(tp);
- xfs_log_sb(tp);
+ if (!bp) {
+ xfs_trans_cancel(tp);
+ return -EIO;
+ }
+ error = xfs_log_sb(tp);
+ if (error) {
+ xfs_trans_cancel(tp);
+ return error;
+ }
xfs_trans_bhold(tp, bp);
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp);
diff --git a/libxfs/xfs_sb.h b/libxfs/xfs_sb.h
index a5e14740..fa7d4496 100644
--- a/libxfs/xfs_sb.h
+++ b/libxfs/xfs_sb.h
@@ -13,7 +13,7 @@ struct xfs_trans;
struct xfs_fsop_geom;
struct xfs_perag;
-extern void xfs_log_sb(struct xfs_trans *tp);
+extern int xfs_log_sb(struct xfs_trans *tp);
extern int xfs_sync_sb(struct xfs_mount *mp, bool wait);
extern int xfs_sync_sb_buf(struct xfs_mount *mp);
extern void xfs_sb_mount_common(struct xfs_mount *mp, struct xfs_sb *sbp);
diff --git a/mkfs/proto.c b/mkfs/proto.c
index ea31cfe5..1e7ad915 100644
--- a/mkfs/proto.c
+++ b/mkfs/proto.c
@@ -589,7 +589,10 @@ parseproto(
if (!pip) {
pip = ip;
mp->m_sb.sb_rootino = ip->i_ino;
- libxfs_log_sb(tp);
+ error = -libxfs_log_sb(tp);
+ if (error) {
+ fail(_("Log sb failed"), error);
+ }
isroot = 1;
} else {
libxfs_trans_ijoin(tp, pip, 0);
@@ -690,7 +693,10 @@ rtinit(
rbmip->i_diflags = XFS_DIFLAG_NEWRTBM;
*(uint64_t *)&VFS_I(rbmip)->i_atime = 0;
libxfs_trans_log_inode(tp, rbmip, XFS_ILOG_CORE);
- libxfs_log_sb(tp);
+ error = -libxfs_log_sb(tp);
+ if (error) {
+ fail(_("Log sb failed"), error);
+ }
mp->m_rbmip = rbmip;
error = -libxfs_dir_ialloc(&tp, NULL, S_IFREG, 1, 0,
&creds, &fsxattrs, &rsumip);
@@ -700,7 +706,10 @@ rtinit(
mp->m_sb.sb_rsumino = rsumip->i_ino;
rsumip->i_disk_size = mp->m_rsumsize;
libxfs_trans_log_inode(tp, rsumip, XFS_ILOG_CORE);
- libxfs_log_sb(tp);
+ error = -libxfs_log_sb(tp);
+ if (error) {
+ fail(_("Log sb failed"), error);
+ }
error = -libxfs_trans_commit(tp);
if (error)
fail(_("Completion of the realtime summary inode failed"),
--
2.27.0
