From: "Darrick J. Wong" djwong@kernel.org
[ Upstream commit c78c2d0903183a41beb90c56a923e30f90fa91b9 ]
I observed the following evidence of a memory leak while running xfs/399 from the xfs fsck test suite (edited for brevity):
XFS (sde): Metadata corruption detected at xfs_attr_shortform_verify_struct.part.0+0x7b/0xb0 [xfs], inode 0x1172 attr fork XFS: Assertion failed: ip->i_af.if_u1.if_data == NULL, file: fs/xfs/libxfs/xfs_inode_fork.c, line: 315 ------------[ cut here ]------------ WARNING: CPU: 2 PID: 91635 at fs/xfs/xfs_message.c:104 assfail+0x46/0x4a [xfs] CPU: 2 PID: 91635 Comm: xfs_scrub Tainted: G W 5.19.0-rc7-xfsx #rc7 6e6475eb29fd9dda3181f81b7ca7ff961d277a40 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 RIP: 0010:assfail+0x46/0x4a [xfs] Call Trace: <TASK> xfs_ifork_zap_attr+0x7c/0xb0 xfs_iformat_attr_fork+0x86/0x110 xfs_inode_from_disk+0x41d/0x480 xfs_iget+0x389/0xd70 xfs_bulkstat_one_int+0x5b/0x540 xfs_bulkstat_iwalk+0x1e/0x30 xfs_iwalk_ag_recs+0xd1/0x160 xfs_iwalk_run_callbacks+0xb9/0x180 xfs_iwalk_ag+0x1d8/0x2e0 xfs_iwalk+0x141/0x220 xfs_bulkstat+0x105/0x180 xfs_ioc_bulkstat.constprop.0.isra.0+0xc5/0x130 xfs_file_ioctl+0xa5f/0xef0 __x64_sys_ioctl+0x82/0xa0 do_syscall_64+0x2b/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0
This newly-added assertion checks that there aren't any incore data structures hanging off the incore fork when we're trying to reset its contents. From the call trace, it is evident that iget was trying to construct an incore inode from the ondisk inode, but the attr fork verifier failed and we were trying to undo all the memory allocations that we had done earlier.
The three assertions in xfs_ifork_zap_attr check that the caller has already called xfs_idestroy_fork, which clearly has not been done here. As the zap function then zeroes the pointers, we've effectively leaked the memory.
The shortest change would have been to insert an extra call to xfs_idestroy_fork, but it makes more sense to bundle the _idestroy_fork call into _zap_attr, since all other callsites call _idestroy_fork immediately prior to calling _zap_attr. IOWs, it eliminates one way to fail.
Note: This change only applies cleanly to 2ed5b09b3e8f, since we just reworked the attr fork lifetime. However, I think this memory leak has existed since 0f45a1b20cd8, since the chain xfs_iformat_attr_fork -> xfs_iformat_local -> xfs_init_local_fork will allocate ifp->if_u1.if_data, but if xfs_ifork_verify_local_attr fails, xfs_iformat_attr_fork will free i_afp without freeing any of the stuff hanging off i_afp. The solution for older kernels I think is to add the missing call to xfs_idestroy_fork just prior to calling kmem_cache_free.
Found by fuzzing a.sfattr.hdr.totsize = lastbit in xfs/399.
[ backport note: did not include refactoring of xfs_idestroy_fork into xfs_ifork_zap_attr, simply added the missing call as suggested in the commit for backports ]
Fixes: 2ed5b09b3e8f ("xfs: make inode attribute forks a permanent part of struct xfs_inode") Probably-Fixes: 0f45a1b20cd8 ("xfs: improve local fork verification") Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Dave Chinner dchinner@redhat.com Signed-off-by: Leah Rumancik leah.rumancik@gmail.com Acked-by: Chandan Babu R chandanbabu@kernel.org --- fs/xfs/libxfs/xfs_inode_fork.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c index 20095233d7bc..c1f965af8432 100644 --- a/fs/xfs/libxfs/xfs_inode_fork.c +++ b/fs/xfs/libxfs/xfs_inode_fork.c @@ -330,6 +330,7 @@ xfs_iformat_attr_fork( }
if (error) { + xfs_idestroy_fork(ip->i_afp); kmem_cache_free(xfs_ifork_zone, ip->i_afp); ip->i_afp = NULL; }