similar to: [PATCH] Export mm_update_next_owner function for vhost-net

On Tue, Dec 18, 2018 at 09:39:16AM +0800, gchen chen wrote: > Yes,?I think so.? > and i think the point is that unuse_mm() can't directly set tsk->mm=NULL. So why can't unuse_mm call mm_update_next_owner? -- MST

This seems like an issue all the unuse_mm users (at least those outside of swapfile.c) have, so it should be solved in the core. Bonus points for moving the set_fs magic into use_mm()..

Switch the function documentation to kerneldoc comments, and add WARN_ON_ONCE asserts that the calling thread is a kernel thread and does not have ->mm set (or has ->mm set in the case of unuse_mm). Also give the functions a kthread_ prefix to better document the use case. Signed-off-by: Christoph Hellwig <hch at lst.de> --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 4 +--

Switch the function documentation to kerneldoc comments, and add WARN_ON_ONCE asserts that the calling thread is a kernel thread and does not have ->mm set (or has ->mm set in the case of unuse_mm). Also give the functions a kthread_ prefix to better document the use case. Signed-off-by: Christoph Hellwig <hch at lst.de> Acked-by: Felix Kuehling <Felix.Kuehling at amd.com> ---

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Acked-by: Andrew Morton <akpm at linux-foundation.org> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47 +---------------------------------- include/linux/mmu_context.h | 9 ++++++

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Acked-by: Andrew Morton <akpm at linux-foundation.org> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47 +---------------------------------- include/linux/mmu_context.h | 9 ++++++

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Acked-by: Andrew Morton <akpm at linux-foundation.org> Acked-by: Andrea Arcangeli <aarcange at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Acked-by: Andrew Morton <akpm at linux-foundation.org> Acked-by: Andrea Arcangeli <aarcange at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47 +---------------------------------- include/linux/mmu_context.h | 9 ++++++ mm/Makefile | 2 +- mm/mmu_context.c

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47 +---------------------------------- include/linux/mmu_context.h | 9 ++++++ mm/Makefile | 2 +- mm/mmu_context.c

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Acked-by: Andrew Morton <akpm at linux-foundation.org> Acked-by: Andrea Arcangeli <aarcange at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Acked-by: Andrew Morton <akpm at linux-foundation.org> Acked-by: Andrea Arcangeli <aarcange at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47

Anyone who wants to do copy to/from user from a kernel thread, needs use_mm (like what fs/aio has). Move that into mm/, to make reusing and exporting easier down the line, and make aio use it. Next intended user, besides aio, will be vhost-net. Acked-by: Andrea Arcangeli <aarcange at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c |

Anyone who wants to do copy to/from user from a kernel thread, needs use_mm (like what fs/aio has). Move that into mm/, to make reusing and exporting easier down the line, and make aio use it. Next intended user, besides aio, will be vhost-net. Acked-by: Andrea Arcangeli <aarcange at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c |

These helpers are only for use with kernel threads, and I will tie them more into the kthread infrastructure going forward. Also move the prototypes to kthread.h - mmu_context.h was a little weird to start with as it otherwise contains very low-level MM bits. Signed-off-by: Christoph Hellwig <hch at lst.de> --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 1 +

And some more information ... Am 2014-10-13 12:04, schrieb Jonas Meurer: > Am 2014-08-19 12:26, schrieb Jonas Meurer: >> I encounter kernel crashes on an up-to-date Debian/Wheezy Xen domU >> with the >> stock kernel. The dom0 runs the same linux kernel and >> xen/4.1.4-3+deb7u1. > > the bug is still reproducible with the latest kernel and Xen packages >

Hey again, Am 2014-08-19 12:26, schrieb Jonas Meurer: > I encounter kernel crashes on an up-to-date Debian/Wheezy Xen domU with > the > stock kernel. The dom0 runs the same linux kernel and > xen/4.1.4-3+deb7u1. the bug is still reproducible with the latest kernel and Xen packages from Debian Wheezy. Unfortunately it seems like a corner case, somehow related to the hardware

* zach@vmware.com (zach@vmware.com) wrote: > This code is quite dead. Release_thread is always guaranteed that the mm has > already been released, thus dead_task->mm will always be NULL. > > Signed-off-by: Zachary Amsden <zach@vmware.com> > Index: linux-2.6.13/arch/i386/kernel/process.c > =================================================================== > ---

* zach@vmware.com (zach@vmware.com) wrote: > This code is quite dead. Release_thread is always guaranteed that the mm has > already been released, thus dead_task->mm will always be NULL. > > Signed-off-by: Zachary Amsden <zach@vmware.com> > Index: linux-2.6.13/arch/i386/kernel/process.c > =================================================================== > ---

The system hang, linux from scratch. I have changed the live kernel from linux-2.6.35.4 to linux-2.6.32.61 , to see if the fault still occurs. The kernel 2.6.35.4 was working fine with all version up to dovecot 2.1.12 , from which i made update to 2.1.17. dovecot -n # 2.1.17: /usr/dovecot21/etc/dovecot/dovecot.conf # OS: Linux 2.6.32.61 i686 auth_cache_negative_ttl = 1 secs auth_cache_size = 2