linux/fs
Andrea Arcangeli dfa37dc3fc userfaultfd: allow signals to interrupt a userfault
This is only simple to achieve if the userfault is going to return to
userland (not to the kernel) because we can avoid returning VM_FAULT_RETRY
despite we temporarily released the mmap_sem.  The fault would just be
retried by userland then.  This is safe at least on x86 and powerpc (the
two archs with the syscall implemented so far).

Hint to verify for which archs this is safe: after handle_mm_fault
returns, no access to data structures protected by the mmap_sem must be
done by the fault code in arch/*/mm/fault.c until up_read(&mm->mmap_sem)
is called.

This has two main benefits: signals can run with lower latency in
production (signals aren't blocked by userfaults and userfaults are
immediately repeated after signal processing) and gdb can then trivially
debug the threads blocked in this kind of userfaults coming directly from
userland.

On a side note: while gdb has a need to get signal processed, coredumps
always worked perfectly with userfaults, no matter if the userfault is
triggered by GUP a kernel copy_user or directly from userland.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-04 16:54:41 -07:00
..
9p 9p: don't leave a half-initialized inode sitting around 2015-07-12 11:22:05 -04:00
adfs fs/adfs: remove unneeded cast 2015-06-30 19:44:57 -07:00
affs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
afs net: Add a struct net parameter to sock_create_kern 2015-05-11 10:50:17 -04:00
autofs4 make simple_positive() public 2015-06-23 18:02:01 -04:00
befs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
bfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
btrfs Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block 2015-09-02 13:10:25 -07:00
cachefiles Merge branch 'fscache-fixes' into for-next 2015-06-23 18:01:30 -04:00
ceph fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
cifs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
coda fs: cleanup slight list_entry abuse 2015-06-23 18:01:59 -04:00
configfs configfs: fix kernel infoleak through user-controlled format string 2015-07-17 16:39:53 -07:00
cramfs
debugfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
devpts devpts: if initialization failed, don't crash when opening /dev/ptmx 2015-06-30 19:44:58 -07:00
dlm dlm for 4.3 2015-09-03 12:57:48 -07:00
ecryptfs treewide: Fix typo in printk 2015-08-07 13:58:05 +02:00
efivarfs Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-05-06 10:57:37 -07:00
efs fs/efs: femove unneeded cast 2015-06-25 17:00:42 -07:00
exofs pagemap.h: move dir_pages() over there 2015-06-23 18:02:00 -04:00
exportfs
ext2 ext2: Handle error from dquot_initalize() 2015-07-23 20:59:37 +02:00
ext4 fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
f2fs Merge tag 'for-f2fs-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs 2015-09-03 13:10:22 -07:00
fat writeback: separate out include/linux/backing-dev-defs.h 2015-06-02 08:33:34 -06:00
freevxfs freevxfs: Grammar s/an negative/a negative/ 2015-08-07 13:59:24 +02:00
fscache FS-Cache: Retain the netfs context in the retrieval op earlier 2015-04-02 14:28:53 +01:00
fuse fs/fuse: fix ioctl type confusion 2015-08-16 12:35:44 -07:00
gfs2 fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hfsplus fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hostfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hpfs hpfs: update ctime and mtime on directory modification 2015-09-03 11:55:30 -07:00
hugetlbfs ipc: use private shmem or hugetlbfs inodes for shm segments. 2015-08-07 04:39:41 +03:00
isofs VFS: normal filesystems (and lustre): d_inode() annotations 2015-04-15 15:06:57 -04:00
jbd2 jbd2: limit number of reserved credits 2015-08-04 11:21:52 -04:00
jffs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
jfs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2015-09-03 12:28:30 -07:00
kernfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-07-03 15:20:57 -07:00
lockd nfsd: eliminate NFSD_DEBUG 2015-04-21 16:16:02 -04:00
logfs block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
minix Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
ncpfs ncpfs: successful rename() should invalidate caches for parents 2015-06-14 11:31:39 -04:00
nfs Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block 2015-09-02 13:10:25 -07:00
nfs_common
nfsd nfsd: do nfs4_check_fh in nfs4_check_file instead of nfs4_check_olstateid 2015-07-31 16:30:26 -04:00
nilfs2 block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
nls
notify fsnotify: get rid of fsnotify_destroy_mark_locked() 2015-09-04 16:54:41 -07:00
ntfs ntfs: delete unnecessary checks before calling iput() 2015-09-04 16:54:41 -07:00
ocfs2 fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
omfs omfs: fix potential integer overflow in allocator 2015-05-28 18:25:19 -07:00
openpromfs
overlayfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
proc userfaultfd: add VM_UFFD_MISSING and VM_UFFD_WP 2015-09-04 16:54:41 -07:00
pstore Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-07-03 15:20:57 -07:00
qnx4
qnx6 pagemap.h: move dir_pages() over there 2015-06-23 18:02:00 -04:00
quota quota: remove an unneeded condition 2015-08-11 10:01:24 +02:00
ramfs VFS: normal filesystems (and lustre): d_inode() annotations 2015-04-15 15:06:57 -04:00
reiserfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
romfs make new_sync_{read,write}() static 2015-04-11 22:29:40 -04:00
squashfs fs: cleanup slight list_entry abuse 2015-06-23 18:01:59 -04:00
sysfs vfs: Commit to never having exectuables on proc and sysfs. 2015-07-10 10:39:25 -05:00
sysv pagemap.h: move dir_pages() over there 2015-06-23 18:02:00 -04:00
tracefs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
ubifs This pull request includes the following UBI/UBIFS changes: 2015-06-25 14:11:34 -07:00
udf udf: Don't modify filesystem for read-only mounts 2015-08-20 14:58:35 +02:00
ufs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
xfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
aio.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-16 23:27:56 -04:00
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
binfmt_script.c
block_dev.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
buffer.c fs: use helper bio_add_page() instead of open coding on bi_io_vec 2015-08-13 12:32:00 -06:00
char_dev.c fs/char_dev.c: fix incorrect documentation for unregister_chrdev_region 2015-08-05 13:49:35 -07:00
compat_binfmt_elf.c
compat_ioctl.c ioctl_compat: handle FITRIM 2015-07-09 11:42:21 -07:00
compat.c
coredump.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
dax.c xfs: call dax_fault on read page faults for DAX 2015-07-29 11:48:00 +10:00
dcache.c fs, file table: reinit files_stat.max_files after deferred memory initialisation 2015-08-07 04:39:40 +03:00
dcookies.c
direct-io.c block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
drop_caches.c
eventfd.c
eventpoll.c
exec.c vfs: Commit to never having exectuables on proc and sysfs. 2015-07-10 10:39:25 -05:00
fcntl.c
fhandle.c vfs: read file_handle only once in handle_to_path 2015-06-02 10:29:07 -07:00
file_table.c fs, file table: reinit files_stat.max_files after deferred memory initialisation 2015-08-07 04:39:40 +03:00
file.c fs/file.c: __fget() and dup2() atomicity rules 2015-07-01 02:31:08 -04:00
filesystems.c
fs_pin.c fs_pin: Allow for the possibility that m_list or s_list go unused. 2015-04-09 11:39:55 -05:00
fs_struct.c
fs-writeback.c writeback: sync_inodes_sb() must write out I_DIRTY_TIME inodes and always call wait_sb_inodes() 2015-08-25 14:35:09 -06:00
inode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
internal.h overlayfs: Make f_path always point to the overlay and f_inode to the underlay 2015-06-19 03:19:32 -04:00
ioctl.c
Kconfig fs: Remove ext3 filesystem driver 2015-07-23 20:59:40 +02:00
Kconfig.binfmt mm: split ET_DYN ASLR from mmap ASLR 2015-04-14 16:49:05 -07:00
libfs.c fs: Set the size of empty dirs to 0. 2015-08-12 15:28:45 -05:00
locks.c locks: inline posix_lock_file_wait and flock_lock_file_wait 2015-07-13 06:29:11 -04:00
Makefile userfaultfd: buildsystem activation 2015-09-04 16:54:41 -07:00
mbcache.c
mount.h fs: use seq_open_private() for proc_mounts 2015-06-30 19:44:56 -07:00
mpage.c block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
namei.c may_follow_link() should use nd->inode 2015-08-04 23:23:50 -04:00
namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-09-01 16:13:25 -07:00
no-block.c
nsfs.c nsfs: Add a show_path method to fix mountinfo 2015-07-11 11:09:00 -05:00
open.c vfs: Commit to never having exectuables on proc and sysfs. 2015-07-10 10:39:25 -05:00
pipe.c VFS: assorted weird filesystems: d_inode() annotations 2015-04-15 15:06:58 -04:00
pnode.c mnt: Don't propagate unmounts to locked mounts 2015-04-02 20:34:20 -05:00
pnode.h mnt: Clarify and correct the disconnect logic in umount_tree 2015-07-22 20:33:27 -05:00
posix_acl.c fs/posix_acl.c: make posix_acl_create() safer and cleaner 2015-06-23 18:01:07 -04:00
proc_namespace.c fs: use seq_open_private() for proc_mounts 2015-06-30 19:44:56 -07:00
read_write.c new_sync_write(): discard ->ki_pos unless the return value is positive 2015-04-11 22:29:46 -04:00
readdir.c
select.c locking/arch: Rename set_mb() to smp_store_mb() 2015-05-19 08:32:00 +02:00
seq_file.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
signalfd.c signalfd: fix information leak in signalfd_copyinfo 2015-08-07 04:39:40 +03:00
splice.c Merge branch 'akpm' (patches from Andrew) 2015-06-24 20:47:21 -07:00
stack.c
stat.c VFS: assorted d_backing_inode() annotations 2015-04-15 15:06:59 -04:00
statfs.c
super.c fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation 2015-07-01 01:50:06 -04:00
sync.c
timerfd.c
userfaultfd.c userfaultfd: allow signals to interrupt a userfault 2015-09-04 16:54:41 -07:00
utimes.c
xattr.c evm: fix potential race when removing xattrs 2015-05-21 13:28:47 -04:00