pkg/report: improve report titles

1. Replace stacktraceRe with custom code which is more flexible.
stacktraceRe stumbled on any unrelated lines and
could not properly parse truncated stacks.

2. Match report regexp earlier.
If we match simler title regexp, but don't match
report regexp or fail to parse stack trace, the report is corrupted.
This eliminates lots of duplicate corrupted oops entries,
which were there only because we had complex regexp's in titles.

3. Ignore low-level frames during stack parsing.
E.g. we never want to report a GPF in lock_acquire or memcpy
(somewhat similar to what we do for guilty files).

4. Add a bunch of specialized formats for WARNINGs.
There is number of generic debugging facilities (like ODEBUG,
debug usercopy, kobject, refcount_t, etc), and the bug
is never in these facilities, it's in the caller instead.

5. Improve some other oops formats.

6. Add a bunch of additional tests.

This resolves most of TODOs in tests.
Fixes #515

1 files changed, 58 insertions, 0 deletions

diff --git a/pkg/report/testdata/linux/guilty/31 b/pkg/report/testdata/linux/guilty/31
new file mode 100644
index 000000000..074c11c5b
--- /dev/null
+++ b/pkg/report/testdata/linux/guilty/31
@@ -0,0 +1,58 @@
+FILE: net/bridge/br_if.c
+
+------------[ cut here ]------------
+WARNING: CPU: 1 PID: 3485 at lib/kobject.c:244 kobject_add_internal+0x3f6/0xbc0 lib/kobject.c:242
+Kernel panic - not syncing: panic_on_warn set ...
+
+CPU: 1 PID: 3485 Comm: syz-executor6 Not tainted 4.14.0-rc4+ #80
+Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
+Call Trace:
+ __dump_stack lib/dump_stack.c:16 [inline]
+ dump_stack+0x194/0x257 lib/dump_stack.c:52
+ panic+0x1e4/0x417 kernel/panic.c:181
+ __warn+0x1c4/0x1d9 kernel/panic.c:542
+ report_bug+0x211/0x2d0 lib/bug.c:183
+ fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178
+ do_trap_no_signal arch/x86/kernel/traps.c:212 [inline]
+ do_trap+0x260/0x390 arch/x86/kernel/traps.c:261
+ do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298
+ do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311
+ invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
+RIP: 0010:kobject_add_internal+0x3f6/0xbc0 lib/kobject.c:242
+RSP: 0018:ffff8801bf816900 EFLAGS: 00010282
+RAX: 0000000000000040 RBX: ffff8801c09b4620 RCX: 0000000000000000
+RDX: 0000000000000040 RSI: ffffffff8158d38e RDI: ffffed0037f02d14
+RBP: ffff8801bf8169f8 R08: ffff8801bf816070 R09: 0000000000000000
+R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10037f02d26
+R13: 00000000fffffff4 R14: ffff8801cb9b0b30 R15: ffff8801cd01c000
+ kobject_add_varg lib/kobject.c:366 [inline]
+ kobject_init_and_add+0xf9/0x150 lib/kobject.c:438
+ br_add_if+0x786/0x1990 net/bridge/br_if.c:533
+ br_add_slave+0x29/0x30 net/bridge/br_device.c:349
+ do_set_master+0x19c/0x1f0 net/core/rtnetlink.c:1986
+ do_setlink+0xa98/0x38e0 net/core/rtnetlink.c:2119
+ rtnl_newlink+0xf0d/0x1a40 net/core/rtnetlink.c:2661
+ rtnetlink_rcv_msg+0x733/0x1090 net/core/rtnetlink.c:4301
+ netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2409
+ rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4313
+ netlink_unicast_kernel net/netlink/af_netlink.c:1273 [inline]
+ netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1299
+ netlink_sendmsg+0xa4a/0xe70 net/netlink/af_netlink.c:1862
+ sock_sendmsg_nosec net/socket.c:633 [inline]
+ sock_sendmsg+0xca/0x110 net/socket.c:643
+ sock_write_iter+0x320/0x5e0 net/socket.c:912
+ call_write_iter include/linux/fs.h:1770 [inline]
+ do_iter_readv_writev+0x531/0x7f0 fs/read_write.c:673
+ do_iter_write+0x15a/0x540 fs/read_write.c:952
+ vfs_writev+0x18a/0x340 fs/read_write.c:997
+ do_writev+0xfc/0x2a0 fs/read_write.c:1032
+ SYSC_writev fs/read_write.c:1105 [inline]
+ SyS_writev+0x27/0x30 fs/read_write.c:1102
+ entry_SYSCALL_64_fastpath+0x1f/0xbe
+RIP: 0033:0x4520a9
+RSP: 002b:00007f4633db3c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000014
+RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004520a9
+RDX: 0000000000000001 RSI: 00000000205d9000 RDI: 0000000000000005
+RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
+R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b6c37
+R13: 00007f4633db3b48 R14: 00000000004b6c47 R15: 0000000000000000