From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Mike Rapoport <rppt@linux.vnet.ibm.com>,
syzbot+121be635a7a35ddb7dcb@syzkaller.appspotmail.com,
Andrea Arcangeli <aarcange@redhat.com>,
Eric Biggers <ebiggers3@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 4.17 23/31] userfaultfd: remove uffd flags from vma->vm_flags if UFFD_EVENT_FORK fails
Date: Sat, 4 Aug 2018 11:00:58 +0200 [thread overview]
Message-ID: <20180804082633.996505438@linuxfoundation.org> (raw)
In-Reply-To: <20180804082632.304529527@linuxfoundation.org>
4.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mike Rapoport <rppt@linux.vnet.ibm.com>
commit 31e810aa1033a7db50a2746cd34a2432237f6420 upstream.
The fix in commit 0cbb4b4f4c44 ("userfaultfd: clear the
vma->vm_userfaultfd_ctx if UFFD_EVENT_FORK fails") cleared the
vma->vm_userfaultfd_ctx but kept userfaultfd flags in vma->vm_flags
that were copied from the parent process VMA.
As the result, there is an inconsistency between the values of
vma->vm_userfaultfd_ctx.ctx and vma->vm_flags which triggers BUG_ON
in userfaultfd_release().
Clearing the uffd flags from vma->vm_flags in case of UFFD_EVENT_FORK
failure resolves the issue.
Link: http://lkml.kernel.org/r/1532931975-25473-1-git-send-email-rppt@linux.vnet.ibm.com
Fixes: 0cbb4b4f4c44 ("userfaultfd: clear the vma->vm_userfaultfd_ctx if UFFD_EVENT_FORK fails")
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Reported-by: syzbot+121be635a7a35ddb7dcb@syzkaller.appspotmail.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/userfaultfd.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -631,8 +631,10 @@ static void userfaultfd_event_wait_compl
/* the various vma->vm_userfaultfd_ctx still points to it */
down_write(&mm->mmap_sem);
for (vma = mm->mmap; vma; vma = vma->vm_next)
- if (vma->vm_userfaultfd_ctx.ctx == release_new_ctx)
+ if (vma->vm_userfaultfd_ctx.ctx == release_new_ctx) {
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
+ vma->vm_flags &= ~(VM_UFFD_WP | VM_UFFD_MISSING);
+ }
up_write(&mm->mmap_sem);
userfaultfd_ctx_put(release_new_ctx);
next prev parent reply other threads:[~2018-08-04 9:03 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-04 9:00 [PATCH 4.17 00/31] 4.17.13-stable review Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 01/31] bonding: avoid lockdep confusion in bond_get_stats() Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 02/31] inet: frag: enforce memory limits earlier Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 03/31] ipv4: frags: handle possible skb truesize change Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 04/31] net: dsa: Do not suspend/resume closed slave_dev Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 05/31] netlink: Fix spectre v1 gadget in netlink_create() Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 06/31] net: stmmac: Fix WoL for PCI-based setups Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 07/31] rxrpc: Fix user call ID check in rxrpc_service_prealloc_one Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 08/31] net/mlx5e: E-Switch, Initialize eswitch only if eswitch manager Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 09/31] net/mlx5e: Set port trust mode to PCP as default Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 10/31] net/mlx5e: IPoIB, Set the netdevice sw mtu in ipoib enhanced flow Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 11/31] squashfs: more metadata hardening Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 13/31] can: ems_usb: Fix memory leak on ems_usb_disconnect() Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 14/31] net: socket: fix potential spectre v1 gadget in socketcall Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 15/31] net: socket: Fix potential spectre v1 gadget in sock_is_registered Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 16/31] virtio_balloon: fix another race between migration and ballooning Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 17/31] x86/efi: Access EFI MMIO data as unencrypted when SEV is active Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 18/31] x86/apic: Future-proof the TSC_DEADLINE quirk for SKX Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 19/31] x86/entry/64: Remove %ebx handling from error_entry/exit Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 20/31] kvm: x86: vmx: fix vpid leak Greg Kroah-Hartman
2018-08-04 9:00 ` [PATCH 4.17 21/31] audit: fix potential null dereference context->module.name Greg Kroah-Hartman
2018-08-04 9:00 ` Greg Kroah-Hartman [this message]
2018-08-04 9:00 ` [PATCH 4.17 24/31] iwlwifi: add more card IDs for 9000 series Greg Kroah-Hartman
2018-08-04 9:01 ` [PATCH 4.17 26/31] RDMA/uverbs: Expand primary and alt AV port checks Greg Kroah-Hartman
2018-08-04 9:01 ` [PATCH 4.17 27/31] crypto: padlock-aes - Fix Nano workaround data corruption Greg Kroah-Hartman
2018-08-04 9:01 ` [PATCH 4.17 28/31] drm/vc4: Reset ->{x, y}_scaling[1] when dealing with uniplanar formats Greg Kroah-Hartman
2018-08-04 9:01 ` [PATCH 4.17 29/31] drm/atomic: Check old_plane_state->crtc in drm_atomic_helper_async_check() Greg Kroah-Hartman
2018-08-04 9:01 ` [PATCH 4.17 30/31] drm/atomic: Initialize variables in drm_atomic_helper_async_check() to make gcc happy Greg Kroah-Hartman
2018-08-04 9:01 ` [PATCH 4.17 31/31] scsi: sg: fix minor memory leak in error path Greg Kroah-Hartman
2018-08-04 14:49 ` [PATCH 4.17 00/31] 4.17.13-stable review Guenter Roeck
2018-08-05 6:54 ` Greg Kroah-Hartman
2018-08-05 11:50 ` Naresh Kamboju
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