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Oleg Nesterov b03023ecbd coredump: add %i/%I in core_pattern to report the tid of the crashed thread 
format_corename() can only pass the leader's pid to the core handler,
but there is no simple way to figure out which thread originated the
coredump.

As Jan explains, this also means that there is no simple way to create
the backtrace of the crashed process:

As programs are mostly compiled with implicit gcc -fomit-frame-pointer
one needs program's .eh_frame section (equivalently PT_GNU_EH_FRAME
segment) or .debug_frame section.  .debug_frame usually is present only
in separate debug info files usually not even installed on the system.
While .eh_frame is a part of the executable/library (and it is even
always mapped for C++ exceptions unwinding) it no longer has to be
present anywhere on the disk as the program could be upgraded in the
meantime and the running instance has its executable file already
unlinked from disk.

One possibility is to echo 0x3f >/proc/*/coredump_filter and dump all
the file-backed memory including the executable's .eh_frame section.
But that can create huge core files, for example even due to mmapped
data files.

Other possibility would be to read .eh_frame from /proc/PID/mem at the
core_pattern handler time of the core dump.  For the backtrace one needs
to read the register state first which can be done from core_pattern
handler:

    ptrace(PTRACE_SEIZE, tid, 0, PTRACE_O_TRACEEXIT)
    close(0);    // close pipe fd to resume the sleeping dumper
    waitpid();   // should report EXIT
    PTRACE_GETREGS or other requests

The remaining problem is how to get the 'tid' value of the crashed
thread.  It could be read from the first NT_PRSTATUS note of the core
file but that makes the core_pattern handler complicated.

Unfortunately %t is already used so this patch uses %i/%I.

Automatic Bug Reporting Tool (https://github.com/abrt/abrt/wiki/overview)
is experimenting with this.  It is using the elfutils
(https://fedorahosted.org/elfutils/) unwinder for generating the
backtraces.  Apart from not needing matching executables as mentioned
above, another advantage is that we can get the backtrace without saving
the core (which might be quite large) to disk.

[mmilata@redhat.com: final paragraph of changelog]
Signed-off-by: Jan Kratochvil <jan.kratochvil@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Mark Wielaard <mjw@redhat.com>
Cc: Martin Milata <mmilata@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2014-10-14 02:18:21 +02:00
..
9p 9p: switch to %p[dD] 2014-10-09 02:39:04 -04:00
adfs adfs: add __printf verification, fix format/argument mismatches 2014-08-08 15:57:24 -07:00
affs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
afs Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 16:23:15 +02:00
autofs4 autofs4: d_manage() should return -EISDIR when appropriate in rcu-walk mode. 2014-10-14 02:18:16 +02:00
befs fs/befs/btree.c: remove typedef befs_btree_node 2014-10-14 02:18:20 +02:00
bfs fs/bfs: use bfs prefix for dump_imap 2014-08-08 15:57:24 -07:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
cachefiles cachefiles_write_page(): switch to __kernel_write() 2014-10-09 02:39:05 -04:00
ceph vfs: Remove d_drop calls from d_revalidate implementations 2014-10-09 02:38:58 -04:00
cifs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
coda fs/coda: use linux/uaccess.h 2014-08-08 15:57:20 -07:00
configfs fs/configfs: use pr_fmt 2014-06-04 16:53:53 -07:00
cramfs fs/cramfs/inode.c: use linux/uaccess.h 2014-08-08 15:57:25 -07:00
debugfs fs: debugfs: remove trailing whitespace 2014-07-09 16:58:21 -07:00
devpts fs/devpts/inode.c: convert printk to pr_foo() 2014-06-06 16:08:14 -07:00
dlm locks: Remove unused conf argument from lm_grant 2014-09-09 16:01:06 -04:00
ecryptfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
efivarfs fs/efivarfs/super.c: use static const for dentry_operations 2014-06-04 16:54:14 -07:00
efs fs/efs/namei.c: return is not a function 2014-08-08 15:57:18 -07:00
exofs fs/exofs/ore_raid.c: replace count*size kzalloc by kcalloc 2014-08-08 15:57:24 -07:00
exportfs fs/exportfs/expfs.c: kernel-doc warning fixes 2014-06-04 16:54:14 -07:00
ext2 percpu_counter: add @gfp to percpu_counter_init() 2014-09-08 09:51:29 +09:00
ext3 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-10-11 08:02:31 -04:00
ext4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block into for-3.18 2014-09-24 13:00:21 -04:00
f2fs f2fs: support volatile operations for transient data 2014-10-07 11:54:41 -07:00
fat fat: remove redundant sys_tz declaration 2014-10-14 02:18:20 +02:00
freevxfs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
fscache FS-Cache: refcount becomes corrupt under vma pressure. 2014-09-17 22:41:40 +01:00
fuse vfs: Make d_invalidate return void 2014-10-09 02:38:57 -04:00
gfs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
hfs fs/hfs/hfs_fs.h: remove redundant sys_tz declaration 2014-10-14 02:18:20 +02:00
hfsplus Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
hostfs hostfs: support rename flags 2014-08-07 14:40:09 -04:00
hpfs fs/hpfs/dnode.c: fix suspect code indent 2014-08-08 15:57:22 -07:00
hppfs
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hugetlbfs fs/hugetlbfs/inode.c: remove null test before kfree 2014-06-04 16:54:11 -07:00
isofs isofs: Fix unbounded recursion when processing relocated directories 2014-08-19 18:29:30 +02:00
jbd fs/jbd/revoke.c: replace shift loop by ilog2 2014-05-21 10:26:13 +02:00
jbd2 jbd2: fix descriptor block size handling errors with journal_csum 2014-08-28 22:22:29 -04:00
jffs2 [jffs2] kill wbuf_queued/wbuf_dwork_lock 2014-10-09 02:39:01 -04:00
jfs Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 16:23:15 +02:00
kernfs vfs: Remove unnecessary calls of check_submounts_and_drop 2014-10-09 02:38:56 -04:00
lockd File locking related changes for v3.18 (pile #1) 2014-10-11 13:21:34 -04:00
logfs fs/logfs/readwrite.c: kernel-doc warning fixes 2014-08-06 18:01:12 -07:00
minix minix zmap block counts calculation fix 2014-08-08 15:57:20 -07:00
ncpfs fs/ncpfs/dir.c: remove redundant sys_tz declaration 2014-10-14 02:18:16 +02:00
nfs Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 16:23:15 +02:00
nfs_common lockd: move lockd's grace period handling into its own module 2014-09-17 16:33:11 -04:00
nfsd Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 16:23:15 +02:00
nilfs2 nilfs2: improve the performance of fdatasync() 2014-10-14 02:18:20 +02:00
nls
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notify File locking related changes for v3.18 (pile #1) 2014-10-11 13:21:34 -04:00
ntfs ntfs: remove bogus space 2014-10-09 22:25:46 -04:00
ocfs2 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-10-11 08:02:31 -04:00
omfs fs/omfs/inode.c: replace count*size kzalloc by kcalloc 2014-08-08 15:57:25 -07:00
openpromfs
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proc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
pstore fs/pstore/ram_core.c: replace count*size kmalloc by kmalloc_array 2014-08-08 15:57:25 -07:00
qnx4
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qnx6 fs/qnx6: update debugging to current functions 2014-08-08 15:57:26 -07:00
quota percpu_counter: add @gfp to percpu_counter_init() 2014-09-08 09:51:29 +09:00
ramfs fs/ramfs/file-nommu.c: replace count*size kzalloc by kcalloc 2014-08-08 15:57:18 -07:00
reiserfs fs/reiserfs/journal.c: fix sparse context imbalance warning 2014-10-14 02:18:20 +02:00
romfs fs/romfs/super.c: add blank line after declarations 2014-08-08 15:57:25 -07:00
squashfs fs/squashfs/super.c: logging cleanup 2014-08-06 18:01:13 -07:00
sysfs kernfs: move the last knowledge of sysfs out from kernfs 2014-06-03 08:11:18 -07:00
sysv write_iter variants of {__,}generic_file_aio_write() 2014-05-06 17:38:00 -04:00
ubifs UBIFS: Add log overlap assertions 2014-07-31 15:52:51 +03:00
udf udf: Fix loading of special inodes 2014-10-09 13:06:14 +02:00
ufs fs/ufs/balloc.c: remove unused variable 2014-10-14 02:18:20 +02:00
xfs Merge branch 'xfs-misc-fixes-for-3.18-3' into for-next 2014-10-13 10:22:45 +11:00
Kconfig lockd: move lockd's grace period handling into its own module 2014-09-17 16:33:11 -04:00
Kconfig.binfmt
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Makefile take fs_pin stuff to fs/* 2014-08-07 14:40:08 -04:00
aio.c percpu_ref: add PERCPU_REF_INIT_* flags 2014-09-24 13:31:50 -04:00
anon_inodes.c vfs: Allocate anon_inode_inode in anon_inode_init() 2014-03-27 09:52:54 -07:00
attr.c fs,userns: Change inode_capable to capable_wrt_inode_uidgid 2014-06-10 13:57:22 -07:00
bad_inode.c bad_inode: add ->rename2() 2014-08-07 14:40:09 -04:00
binfmt_aout.c handle suicide on late failure exits in execve() in search_binary_handler() 2014-10-09 02:39:00 -04:00
binfmt_elf.c handle suicide on late failure exits in execve() in search_binary_handler() 2014-10-09 02:39:00 -04:00
binfmt_elf_fdpic.c handle suicide on late failure exits in execve() in search_binary_handler() 2014-10-09 02:39:00 -04:00
binfmt_em86.c
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binfmt_flat.c fs/binfmt_flat.c: make old_reloc() static 2014-06-04 16:54:21 -07:00
binfmt_misc.c binfmt_misc: work around gcc-4.9 warning 2014-10-14 02:18:16 +02:00
binfmt_script.c
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binfmt_som.c
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block_dev.c block_dev: implement readpages() to optimize sequential read 2014-10-09 22:25:53 -04:00
buffer.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
char_dev.c
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compat.c vfs: move getname() from callers to do_mount() 2014-10-09 02:39:16 -04:00
compat_binfmt_elf.c
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compat_ioctl.c Bluetooth: Move HCI socket definitions into its own header file 2014-07-11 13:53:04 +03:00
coredump.c coredump: add %i/%I in core_pattern to report the tid of the crashed thread 2014-10-14 02:18:21 +02:00
dcache.c take dname_external() into fs/dcache.c 2014-10-12 17:09:05 -04:00
dcookies.c
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direct-io.c fuse: honour max_read and max_write in direct_io mode 2014-09-26 21:16:51 -04:00
drop_caches.c fs: convert use of typedef ctl_table to struct ctl_table 2014-06-06 16:08:16 -07:00
eventfd.c
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eventpoll.c eventpoll: fix uninitialized variable in epoll_ctl 2014-09-10 15:42:12 -07:00
exec.c handle suicide on late failure exits in execve() in search_binary_handler() 2014-10-09 02:39:00 -04:00
fcntl.c security: make security_file_set_fowner, f_setown and __f_setown void return 2014-09-09 16:01:36 -04:00
fhandle.c
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file.c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 15:44:12 +02:00
file_table.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
filesystems.c sys_sysfs: Add CONFIG_SYSFS_SYSCALL 2014-04-03 16:21:05 -07:00
fs-writeback.c sched: Remove proliferation of wait_on_bit() action functions 2014-07-16 15:10:39 +02:00
fs_pin.c make fs/{namespace,super}.c forget about acct.h 2014-08-07 14:40:09 -04:00
fs_struct.c
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inode.c mm: allow drivers to prevent new writable mappings 2014-08-08 15:57:31 -07:00
internal.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
ioctl.c
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libfs.c locks: plumb a "priv" pointer into the setlease routines 2014-10-07 14:06:12 -04:00
locks.c locks: flock_make_lock should return a struct file_lock (or PTR_ERR) 2014-10-07 14:06:13 -04:00
mbcache.c fs/mbcache: replace __builtin_log2() with ilog2() 2014-06-25 22:08:29 -04:00
mount.h vfs: Add a function to lazily unmount all mounts from any dentry. 2014-10-09 02:38:55 -04:00
mpage.c vfs: guard end of device for mpage interface 2014-10-09 22:25:53 -04:00
namei.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
namespace.c vfs: move getname() from callers to do_mount() 2014-10-09 02:39:16 -04:00
no-block.c
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open.c vfs: fix check for fallocate on active swapfile 2014-08-01 02:36:04 -04:00
pipe.c new helper: copy_page_from_iter() 2014-05-06 17:39:42 -04:00
pnode.c get rid of propagate_umount() mistakenly treating slaves as busy. 2014-08-30 18:31:41 -04:00
pnode.h smarter propagate_mnt() 2014-04-01 23:19:08 -04:00
posix_acl.c posix_acl: handle NULL ACL in posix_acl_equiv_mode 2014-05-06 13:58:42 -04:00
proc_namespace.c namespaces: Use task_lock and not rcu to protect nsproxy 2014-07-29 18:08:50 -07:00
read_write.c cachefiles_write_page(): switch to __kernel_write() 2014-10-09 02:39:05 -04:00
readdir.c fanotify: create FAN_ACCESS event for readdir 2014-06-04 16:53:52 -07:00
select.c
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seq_file.c fs/seq_file: fallback to vmalloc allocation 2014-07-03 09:21:54 -07:00
signalfd.c
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splice.c Merge commit '9f12600fe425bc28f0ccba034a77783c09c15af4' into for-linus 2014-06-12 00:28:09 -04:00
stack.c fs: fix comment for 'CONFIG_LBADF' 2014-08-26 09:35:56 +02:00
stat.c
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statfs.c
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super.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-10-13 11:28:42 +02:00
sync.c Export sync_filesystem() for modular ->remount_fs() use 2014-09-05 08:16:21 -07:00
timerfd.c timerfd: Remove an always true check 2014-08-27 11:17:48 +02:00
utimes.c
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xattr.c vfs: Deduplicate code shared by xattr system calls operating on paths 2014-10-12 17:09:10 -04:00