| Message ID | cover.1671194454.git.bcodding@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Stop corrupting socket's task_frag | expand |
Hello: This series was applied to netdev/net.git (master) by Jakub Kicinski <kuba@kernel.org>: On Fri, 16 Dec 2022 07:45:25 -0500 you wrote: > The networking code uses flags in sk_allocation to determine if it can use > current->task_frag, however in-kernel users of sockets may stop setting > sk_allocation when they convert to the preferred memalloc_nofs_save/restore, > as SUNRPC has done in commit a1231fda7e94 ("SUNRPC: Set memalloc_nofs_save() > on all rpciod/xprtiod jobs"). > > This will cause corruption in current->task_frag when recursing into the > network layer for those subsystems during page fault or reclaim. The > corruption is difficult to diagnose because stack traces may not contain the > offending subsystem at all. The corruption is unlikely to show up in > testing because it requires memory pressure, and so subsystems that > convert to memalloc_nofs_save/restore are likely to continue to run into > this issue. > > [...] Here is the summary with links: - [net,v4,1/3] net: Introduce sk_use_task_frag in struct sock. https://git.kernel.org/netdev/net/c/fb87bd47516d - [net,v4,2/3] Treewide: Stop corrupting socket's task_frag https://git.kernel.org/netdev/net/c/98123866fcf3 - [net,v4,3/3] net: simplify sk_page_frag https://git.kernel.org/netdev/net/c/08f65892c5ee You are awesome, thank you!
The networking code uses flags in sk_allocation to determine if it can use current->task_frag, however in-kernel users of sockets may stop setting sk_allocation when they convert to the preferred memalloc_nofs_save/restore, as SUNRPC has done in commit a1231fda7e94 ("SUNRPC: Set memalloc_nofs_save() on all rpciod/xprtiod jobs"). This will cause corruption in current->task_frag when recursing into the network layer for those subsystems during page fault or reclaim. The corruption is difficult to diagnose because stack traces may not contain the offending subsystem at all. The corruption is unlikely to show up in testing because it requires memory pressure, and so subsystems that convert to memalloc_nofs_save/restore are likely to continue to run into this issue. Previous reports and proposed fixes: https://lore.kernel.org/netdev/96a18bd00cbc6cb554603cc0d6ef1c551965b078.1663762494.git.gnault@redhat.com/ https://lore.kernel.org/netdev/b4d8cb09c913d3e34f853736f3f5628abfd7f4b6.1656699567.git.gnault@redhat.com/ https://lore.kernel.org/linux-nfs/de6d99321d1dcaa2ad456b92b3680aa77c07a747.1665401788.git.gnault@redhat.com/ Guilluame Nault has done all of the hard work tracking this problem down and finding the best fix for this issue. I'm just taking a turn posting another fix. Changes on v2: - rebased on -net - set sk_use_task_frag = false for xfrm/espintcp.c Changes on v3: - fixup comments in sock.h for kernel-doc Changes on v4: - rebased on -net - sk_use_task_frag moved to hole after sk_txtime_unused - droppd afs/rxrpc.c hunk, not needed Benjamin Coddington (2): Treewide: Stop corrupting socket's task_frag net: simplify sk_page_frag Guillaume Nault (1): net: Introduce sk_use_task_frag in struct sock. drivers/block/drbd/drbd_receiver.c | 3 +++ drivers/block/nbd.c | 1 + drivers/nvme/host/tcp.c | 1 + drivers/scsi/iscsi_tcp.c | 1 + drivers/usb/usbip/usbip_common.c | 1 + fs/cifs/connect.c | 1 + fs/dlm/lowcomms.c | 2 ++ fs/ocfs2/cluster/tcp.c | 1 + include/net/sock.h | 10 ++++++---- net/9p/trans_fd.c | 1 + net/ceph/messenger.c | 1 + net/core/sock.c | 1 + net/sunrpc/xprtsock.c | 3 +++ net/xfrm/espintcp.c | 1 + 14 files changed, 24 insertions(+), 4 deletions(-)