From 3caa0c6ed754d91b15266abf222498edbef982bd Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 13 Oct 2014 10:26:43 -0400 Subject: NFS: Fix an uninitialised pointer Oops in the writeback error path SteveD reports the following Oops: RIP: 0010:[] [] __put_nfs_open_context+0x1d/0x100 [nfs] RSP: 0018:ffff880fed687b90 EFLAGS: 00010286 RAX: 0000000000000024 RBX: 0000000000000000 RCX: 0000000000000006 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff880fed687bc0 R08: 0000000000000092 R09: 000000000000047a R10: 0000000000000000 R11: ffff880fed6878d6 R12: ffff880fed687d20 R13: ffff880fed687d20 R14: 0000000000000070 R15: ffffea000aa33ec0 FS: 00007fce290f0740(0000) GS:ffff8807ffc60000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000070 CR3: 00000007f2e79000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: 0000000000000000 ffff880036c5e510 ffff880fed687d20 ffff880fed687d20 ffff880036c5e200 ffffea000aa33ec0 ffff880fed687bd0 ffffffffa0534710 ffff880fed687be8 ffffffffa053d5f0 ffff880036c5e200 ffff880fed687c08 Call Trace: [] put_nfs_open_context+0x10/0x20 [nfs] [] nfs_pgio_data_destroy+0x20/0x40 [nfs] [] nfs_pgio_error+0x22/0x40 [nfs] [] nfs_generic_pgio+0x74/0x2e0 [nfs] [] pnfs_generic_pg_writepages+0x63/0x210 [nfsv4] [] nfs_pageio_doio+0x19/0x50 [nfs] [] nfs_pageio_complete+0x24/0x30 [nfs] [] nfs_direct_write_schedule_iovec+0x115/0x1f0 [nfs] [] ? nfs_get_lock_context+0x4f/0x120 [nfs] [] nfs_file_direct_write+0x262/0x420 [nfs] [] nfs_file_write+0x131/0x1d0 [nfs] [] ? nfs_need_sync_write.isra.17+0x40/0x40 [nfs] [] do_io_submit+0x3b8/0x840 [] SyS_io_submit+0x10/0x20 [] system_call_fastpath+0x16/0x1b This is due to the calls to nfs_pgio_error() in nfs_generic_pgio(), which happen before the nfs_pgio_header's open context is referenced in nfs_pgio_rpcsetup(). Reported-by: Steve Dickson Cc: stable@vger.kernel.org # 3.16.x Signed-off-by: Trond Myklebust --- fs/nfs/pagelist.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 94e16ec88312..08085de879ed 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -526,7 +526,8 @@ EXPORT_SYMBOL_GPL(nfs_pgio_header_free); */ void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr) { - put_nfs_open_context(hdr->args.context); + if (hdr->args.context) + put_nfs_open_context(hdr->args.context); if (hdr->page_array.pagevec != hdr->page_array.page_array) kfree(hdr->page_array.pagevec); } -- cgit v1.2.3