Commit Graph

8 Commits

Author SHA1 Message Date
Christopher Ferris c463ba45c4 Add error reporting mechanism for failing Unwind.
Remove the logging of an error if a thread disappears before the unwind
can begin. This can happen, so allow the caller to determine if this
is really a problem worth logging.

Bug: 27449879

(cherry picked from commit 206a3b9798)

Change-Id: If9e7cfeb6eb7b122679a734c1a9eacee8354ef18
2016-03-10 14:14:43 -08:00
Yabin Cui 6405bb3aee Fix libbacktrace host build.
On host build, libbacktrace relies on libcutils to provide gettid()
function.

Change-Id: Iad83384ea699ca024b71b73cef26755287c9e6fe
2015-12-07 20:09:24 -08:00
Christopher Ferris d7226f9a14 Add a logging handler on timeout.
If the signal handler doesn't fire in the given time when trying to unwind
a thread, put on a logging handler. This prevents crashes if the signal
does eventually fire.

Bug: 23783762
Change-Id: Ib7abb36b71d079a7043117697c41b535319586fd
2015-09-03 12:27:57 -07:00
Christopher Ferris 2d09171758 Modify the code to avoid potential deadlocks.
If the signal to dump a thread is never delivered, then it's
possible for a deadlock. The signal handler is responsible for
unlocking and deleting the ThreadEntry created for the pid/tid
combination. This means if the signal is lost, the ThreadEntry
gets stuck locked and never deleted. If a second attempt to get
a backtrace of this thread occurs, there is a deadlock.

Also, decrease the timeout from 10 seconds to 5 seconds. The original
10 seconds was because the unwind was actually done in the signal
handler. Now the signal handler does nothing but copy the ucontext
structure and let the caller do the unwind.

Bug: 21086132
Change-Id: Idc735dbf6147ec879d35bd4f034c5d227e26a98d
2015-06-01 13:51:51 -07:00
Christopher Ferris 30c942cf10 Prevent crashes if a map cannot be created.
Under some conditions, /proc/<pid>/maps might return nothing. If we
try and unwind in this case, we'll crash. Check this case and fail
the unwind.

Add checks that no other functions try and use map_ without
checking for nullptr.

Add logging when an unwind fails so it's clear what happened.

Bug: 21162746
Change-Id: I56ce51dda0cfc9db20475a441f118108196aa07c
2015-05-14 17:56:41 -07:00
Dan Albert 23f750b068 Remove libbacktrace definition of gettid.
Also simplifies the Darwin implementation of gettid, because
apparently libbacktrace had a better way of doing it.

Change-Id: I9e14f9176b167405a5aaa5b8a0db0327c7126271
2015-04-30 12:52:21 -07:00
Christopher Ferris ca09ce902c Discards frames for code within library.
When doing a local unwind, do not include the frames that come
from either libunwind or libbacktrace.

Bug: 11518609
Change-Id: I0ec8d823aebbfa0903e61b16b7e5663f3fd65e78
2015-04-01 15:58:20 -07:00
Christopher Ferris 2c43cff01d Refactor the code.
The object hierarchy was confusing and convoluted. This removes
a lot of unnecessary code, and consolidates the BacktraceCurrent
and BacktraceThread code into BacktraceCurrent.

Change-Id: I01c8407d493712a48169df49dd3ff46db4a7c3ae
2015-03-31 10:51:44 -07:00