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remarkable-linux/fs
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Neil Horman 61be228a06 exec: allow do_coredump() to wait for user space pipe readers to complete 
Allow core_pattern pipes to wait for user space to complete

One of the things that user space processes like to do is look at metadata
for a crashing process in their /proc/<pid> directory.  this is racy
however, since do_coredump in the kernel doesn't wait for the user space
process to complete before it reaps the crashing process.  This patch
corrects that.  Allowing the kernel to wait for the user space process to
complete before cleaning up the crashing process.  This is a bit tricky to
do for a few reasons:

1) The user space process isn't our child, so we can't sys_wait4 on it
2) We need to close the pipe before waiting for the user process to complete,
since the user process may rely on an EOF condition

I've discussed several solutions with Oleg Nesterov off-list about this,
and this is the one we've come up with.  We add ourselves as a pipe reader
(to prevent premature cleanup of the pipe_inode_info), and remove
ourselves as a writer (to provide an EOF condition to the writer in user
space), then we iterate until the user space process exits (which we
detect by pipe->readers == 1, hence the > 1 check in the loop).  When we
exit the loop, we restore the proper reader/writer values, then we return
and let filp_close in do_coredump clean up the pipe data properly.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Earl Chew <earl_chew@agilent.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:21:00 -07:00
..
9p 9p: Add fscache support to 9p 2009-09-23 13:03:46 -05:00
adfs headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
affs affs: add ->sync_fs 2009-06-11 21:36:14 -04:00
afs seq_file: constify seq_operations 2009-09-23 07:39:29 -07:00
autofs trivial: remove unnecessary semicolons 2009-09-21 15:14:58 +02:00
autofs4 autofs4 - fix missed case when changing to use struct path 2009-08-31 17:44:05 -10:00
befs const: mark remaining super_operations const 2009-09-22 07:17:24 -07:00
bfs headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-09-22 07:51:45 -07:00
cachefiles enforce ->sync_fs is only called for rw superblock 2009-06-11 21:36:06 -04:00
cifs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-09-22 07:51:45 -07:00
coda splice: implement default splice_read method 2009-05-11 14:13:10 +02:00
configfs writeback: add name to backing_dev_info 2009-09-11 09:20:26 +02:00
cramfs fs/cramfs: return f_fsid for statfs(2) 2009-04-02 19:05:08 -07:00
debugfs debugfs: use specified mode to possibly mark files read/write only 2009-06-15 21:30:28 -07:00
devpts Move magic numbers into magic.h 2009-09-23 07:39:28 -07:00
dlm seq_file: constify seq_operations 2009-09-23 07:39:29 -07:00
ecryptfs const: mark remaining address_space_operations const 2009-09-22 07:17:24 -07:00
efs get rid of BKL in fs/efs 2009-06-17 00:36:36 -04:00
exofs headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
exportfs
ext2 ext2: fix format string compile warning (ino_t) 2009-09-23 07:39:58 -07:00
ext3 const: make struct super_block::s_qcop const 2009-09-22 07:17:24 -07:00
ext4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-09-22 07:51:45 -07:00
fat fat: Opencode sync_page_range_nolock() 2009-09-14 17:08:17 +02:00
freevxfs headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
fscache FS-Cache: Fixup renamed filenames in comments in internal.h 2009-05-27 10:20:13 -07:00
fuse Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse 2009-09-18 09:23:03 -07:00
gfs2 headers: utsname.h redux 2009-09-23 18:13:10 -07:00
hfs headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
hfsplus headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
hostfs hostfs: set maximum filesize in superblock for proper LFS support 2009-06-30 18:56:03 -07:00
hpfs headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
hppfs hppfs: hppfs_read_file() may return -ERROR 2009-04-02 19:04:53 -07:00
hugetlbfs hugetlbfs: do not call user_shm_lock() for MAP_HUGETLB fix 2009-09-24 07:20:56 -07:00
isofs isofs: fix Joliet regression 2009-07-10 19:18:59 -07:00
jbd jbd: Annotate transaction start also for journal_restart() 2009-09-16 17:44:10 +02:00
jbd2 seq_file: constify seq_operations 2009-09-23 07:39:29 -07:00
jffs2 Merge git://git.infradead.org/mtd-2.6 2009-09-23 10:07:49 -07:00
jfs jffs2/jfs/xfs: switch over to 'check_acl' rather than 'permission()' 2009-09-08 11:09:04 -07:00
lockd headers: utsname.h redux 2009-09-23 18:13:10 -07:00
minix V3 minixfs: add missing directory type checking 2009-09-23 07:39:57 -07:00
ncpfs ncpfs: fix wrong check in __ncp_ioctl() 2009-09-23 07:39:42 -07:00
nfs headers: utsname.h redux 2009-09-23 18:13:10 -07:00
nfs_common
nfsd headers: utsname.h redux 2009-09-23 18:13:10 -07:00
nilfs2 const: mark remaining inode_operations as const 2009-09-22 07:17:24 -07:00
nls NLS: update handling of Unicode 2009-06-15 21:44:43 -07:00
notify inotify: update the group mask on mark addition 2009-08-28 12:51:14 -04:00
ntfs ntfs: remove ntfs_file_write 2009-09-23 07:39:29 -07:00
ocfs2 headers: utsname.h redux 2009-09-23 18:13:10 -07:00
omfs const: mark remaining inode_operations as const 2009-09-22 07:17:24 -07:00
openpromfs
partitions const: make block_device_operations const 2009-09-22 07:17:25 -07:00
proc /proc/kcore: update stat.st_size after memory hotplug 2009-09-23 07:39:42 -07:00
qnx4 qnx4: remove write support 2009-09-23 07:39:30 -07:00
quota const: make struct super_block::s_qcop const 2009-09-22 07:17:24 -07:00
ramfs ramfs: move RAMFS_MAGIC to include/linux/magic.h 2009-09-23 07:39:42 -07:00
reiserfs const: make struct super_block::s_qcop const 2009-09-22 07:17:24 -07:00
romfs const: mark remaining inode_operations as const 2009-09-22 07:17:24 -07:00
smbfs smbfs: read buffer overflow 2009-09-23 07:39:27 -07:00
squashfs const: mark remaining super_operations const 2009-09-22 07:17:24 -07:00
sysfs Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-block 2009-09-11 09:17:05 -07:00
sysv get rid of BKL in fs/sysv 2009-06-17 00:36:37 -04:00
ubifs const: mark remaining address_space_operations const 2009-09-22 07:17:24 -07:00
udf udf: Fix possible corruption when close races with write 2009-09-14 19:13:01 +02:00
ufs ufs: sector_t cannot be negative 2009-06-18 13:03:46 -07:00
xfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-09-22 07:51:45 -07:00
aio.c aio.c: move EXPORT* macros to line after function 2009-09-23 07:39:29 -07:00
anon_inodes.c anonfd: split interface into file creation and install 2009-09-23 07:39:29 -07:00
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf.c mm: add get_dump_page 2009-09-22 07:17:40 -07:00
binfmt_elf_fdpic.c mm: add get_dump_page 2009-09-22 07:17:40 -07:00
binfmt_em86.c
binfmt_flat.c flat: fix uninitialized ptr with shared libs 2009-08-07 10:39:57 -07:00
binfmt_misc.c
binfmt_script.c
binfmt_som.c Don't crap into descriptor table in binfmt_som 2009-03-31 23:00:28 -04:00
bio-integrity.c block: Create bip slabs with embedded integrity vectors 2009-07-01 10:56:25 +02:00
bio.c block: fix sg SG_DXFER_TO_FROM_DEV regression 2009-07-10 20:31:53 +02:00
block_dev.c const: make block_device_operations const 2009-09-22 07:17:25 -07:00
buffer.c fs/buffer.c: clean up EXPORT* macros 2009-09-23 07:39:29 -07:00
char_dev.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6 2009-09-11 09:19:35 -07:00
compat.c fix compat_sys_utimensat() 2009-09-23 07:39:30 -07:00
compat_binfmt_elf.c
compat_ioctl.c compat_ioctl: hook up compat handler for FIEMAP ioctl 2009-08-07 10:39:56 -07:00
dcache.c sched: Pull up the might_sleep() check into cond_resched() 2009-07-18 15:51:44 +02:00
dcookies.c
direct-io.c block: Do away with the notion of hardsect_size 2009-05-22 23:22:54 +02:00
drop_caches.c mm: remove __invalidate_mapping_pages variant 2009-06-16 19:47:43 -07:00
eventfd.c anonfd: split interface into file creation and install 2009-09-23 07:39:29 -07:00
eventpoll.c epoll: fix nested calls support 2009-06-18 13:03:41 -07:00
exec.c exec: allow do_coredump() to wait for user space pipe readers to complete 2009-09-24 07:21:00 -07:00
fcntl.c headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
fifo.c
file.c
file_table.c fs: move mark_files_ro into file_table.c 2009-06-11 21:36:02 -04:00
filesystems.c fs: Mark get_filesystem_list() as __init function. 2009-04-20 23:02:52 -04:00
fs-writeback.c writeback: fix possible bdi writeback refcounting problem 2009-09-16 15:18:53 +02:00
fs_struct.c Get rid of indirect include of fs_struct.h 2009-03-31 23:00:27 -04:00
generic_acl.c New helper - current_umask() 2009-03-31 23:00:26 -04:00
inode.c fs: turn iprune_mutex into rwsem 2009-09-23 07:39:29 -07:00
internal.h Trim a bit of crap from fs.h 2009-06-11 21:36:07 -04:00
ioctl.c fs: Add new pre-allocation ioctls to vfs for compatibility with legacy xfs ioctls 2009-06-24 08:15:27 -04:00
ioprio.c
Kconfig tmpfs: depend on shmem 2009-09-22 07:17:41 -07:00
Kconfig.binfmt
libfs.c vfs: make get_sb_pseudo set s_maxbytes to value that can be cast to signed 2009-08-18 16:31:12 -07:00
locks.c const: make lock_manager_operations const 2009-09-22 07:17:25 -07:00
Makefile nilfs2: update makefile and Kconfig 2009-04-07 08:31:16 -07:00
mbcache.c
mpage.c ext4: Properly initialize the buffer_head state 2009-05-13 15:13:42 -04:00
namei.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2009-09-11 08:55:49 -07:00
namespace.c vfs: mnt_want_write_file(): fix special file handling 2009-08-07 10:39:56 -07:00
nfsctl.c
no-block.c
open.c fs: change sys_truncate length parameter type 2009-09-23 09:21:05 -07:00
pipe.c lockdep: Fix lockdep annotation for pipe_double_lock() 2009-07-22 21:14:14 +02:00
pnode.c
pnode.h
posix_acl.c
read_write.c splice: implement default splice_read method 2009-05-11 14:13:10 +02:00
read_write.h
readdir.c
select.c poll/select: avoid arithmetic overflow in __estimate_accuracy() 2009-09-23 07:39:27 -07:00
seq_file.c seq_file: add function to write binary data 2009-06-18 13:03:57 -07:00
signalfd.c
splice.c Merge branch 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block 2009-09-14 17:55:15 -07:00
stack.c
stat.c kill vfs_stat_fd / vfs_lstat_fd 2009-04-20 23:02:52 -04:00
super.c const: mark remaining super_operations const 2009-09-22 07:17:24 -07:00
sync.c fs/buffer.c: clean up EXPORT* macros 2009-09-23 07:39:29 -07:00
timerfd.c
utimes.c
xattr.c VFS: Factor out part of vfs_setxattr so it can be called from the SELinux hook for inode_setsecctx. 2009-09-10 10:11:22 +10:00
xattr_acl.c