Some changes to debuggerd:
(1) Send a SIGSTOP to the target process before doing any of the
PTRACE_ATTACH work. This causes the threads that weren't hit by
the signal to stop moving, which seems to get rid of the "ptrace
detach failed: No such process" problems that result in missed
stack traces and debuggerd self-immolation.
(2) SIGPIPE was in the list of "interesting" signals caught by
debugger_signal_handler(), but debuggerd didn't recognize it, and
you'd get "unexpected signal 13" complaints. It's now in the list.
(3) Fixed a bit-rotted XLOG.
Change-Id: I33297ea6b09ce450671c07dc25846f684afbf480
Show the symbol offset, when available.
Centralized formatting of native stack traces in libcorkscrew.
It's handy for automated tools if all stacks look the same.
Since we already made them all look them same, we might as well
do the formatting in just one place.
Do not strip the Thumb bit on ARM. This fixes an off-by-one
issue that could happen when resolving a PC that was at the
very beginning of a Thumb function, since the symbol table would
have the Thumb bit set but since we stripped the bit from our
PC, we would be looking for an address one byte before the
one listed in the symbol table. It's also quite useful to see
whether a given function is executing in Thumb mode just by glancing
at the PC.
Change-Id: Icaa29add85ce0bcafe24d5ce2098e138d809e2ab
When explicitly requesting a dump, show the user the path of
the tombstone file that was generated.
Change-Id: I7fff7dea606872a61687ca087e99f604107b70c4
Keep track of whether memory maps are readable. Use the information
in try_get_word to try to avoid accidentally dereferencing an invalid
pointer within the current process. (Note that I haven't ever
seen that happen during normal unwinding, but it pays to be
a little more careful.)
Refactored try_get_word a little to make it easier to pass it the
needed state for validation checks by way of a little memory_t struct.
Improved how the memory map for the current process is cached. This is
important because we need up to date information about readable maps.
Use a 5 second cache expiration.
Improved the PC -> LR fallback logic in the unwinder so we can
eke out an extra frame sometimes.
Fixed a bug reading ELF program headers. The phnum & phentsize
fields are half-words. We were incorrectly interpreting
phnum as a whole word.
Used android_atomic_* operations carefully in the unwinder
to prevent possible memory races between the dumper and the dumpee.
This was highly unlikely (or even impossible due to the presence
of other barriers along the way) but the code is clearer now about
its invariants.
Fixed a bug in debuggerd where the pid was being passed to have
its stack dump taken instead of the tid, resulting in short
stacks because ptrace couldn't read the data if pid != tid.
Did a full sweep to ensure that we use pid / tid correctly everywhere.
Ported old code from debuggerd to rewind the program counter back
one instruction so that it points to the branch instruction itself
instead of the return address.
Change-Id: Icc4eb08320052975a4ae7f0f5f0ac9308a2d33d7
This change modifies debuggerd so that it can be used to grab
the native stacks of a process that has hung and not just crashed.
Note that only the root user can do this (for now).
adb shell debuggerd <tid>
Then use logcat to find the tombstone file that was generated
which will have the native stacks of all threads in the
requested process. The specified thread will be shown first
and will also appear in the main log.
Also made some minor tweaks to libcorkscrew so that we
could handle statically compiled executables in the future
if we compiled the library statically.
Improved the "wait_for_user_action" function to support
volume down as an alternative for devices that do not
have home keys.
Removed a mess of gotos.
Change-Id: Ic149653986b0c2f503c7f0e8b7cb1f3be7c84d1e
Dump some memory at addresses for all registers that look like they
might have valid addresses. Previously this was only done for PC
and LR.
(This is expected to be disabled before ship.)
Bug 5484924
Change-Id: I9802eaa396783e1286ae0c53eaf2473892c38a02
When the tombstones are uploaded to APR, they're truncated at 64KB.
This causes the log data, which is at the end, to be lost if the
process has more than about 12 threads (which many do).
This change adds the last few lines of the log right below the
report for the crashing thread, where we should be guaranteed to
keep it.
Also, clean up trailing newlines on log messages (which end up in
the tombstone), and don't print a "------- log" banner if there
aren't any messages in that log file (e.g. slog).
Also also, don't try to show_nearby_maps unless this is the crashing
thread.
Bug 5471955
Change-Id: Iaa4fd2fafbaeda2f20bb95f202177d7744a91f9d
This makes two changes:
(1) Display ASCII values next to the memory dumps. For example:
I DEBUG: 00008ac4 706f6f4c 20676e69 74206425 73656d69 Looping %d times
I DEBUG: 00008ad4 7453000a 6e69726f 6f742067 0a702520 ..Storing to %p.
I DEBUG: 00008ae4 65642f00 657a2f76 55006f72 6c62616e ./dev/zero.Unabl
(The hex values are still displayed as little-endian word values, while
the ASCII part is byte oriented.)
(2) Optionally display memory dumps for all registers, not just LR
and PC, for the crashing thread. This is meant for situations where
we crash dereferencing foo->bar and want to see what the memory near
"foo" looks like -- could be handy if it got stomped by MUTF-16 text
or something recognizable.
Change #2 is currently disabled, via a compile-time setting.
Bug 5471955
Change-Id: Iacfd01c314055bad81db2f43b7d239f10086fcfb
The Android Problem Report site shows tombstones uploaded from
devices. We can see the native stack traces for every thread,
but sometimes there's a very important bit of information sitting
in the log, and without it we can't analyze the failure.
This change modifies debuggerd so that the log contents for the
crashing process are appended to the tombstone. The format matches
the output of "logcat -v threadtime". Both "system" and "main" logs
are included (but not interleaved -- we're not that fancy).
This feature is only enabled when the "ro.debuggable" system property
is set to 1 (indicating a development device).
Bug 5456676
Change-Id: I3be1df59813ccf1058cec496a906f6d31fbc7b04
This adds some additional output to native crashes. For example, if
something tried to access a bit of mmap(/dev/zero) memory that had
been mprotect()ed, you might see output like this:
I DEBUG : memory map around addr 4015a00c:
I DEBUG : 40159000-4015a000 /system/lib/libstdc++.so
I DEBUG : 4015a000-40162000 /dev/zero
I DEBUG : b0001000-b0009000 /system/bin/linker
The idea is to see what's in and around the fault address to make it
easier to identify bus errors due to file truncation and segmentation
faults caused by buffer over/underruns.
No output is generated for accesses below 0x1000 (which are likely
NULL pointer dereferences) or for signals that don't set si_addr.
Also, suppress the fault address for signals that don't set si_addr:
I DEBUG : signal 6 (SIGABRT), code 0 (?), fault addr --------
We still print "fault addr" followed by 8 characters for anything
that is parsing the contents. The "address" shown for signals like
SIGABRT was meaningless and possibly confusing.
Bug 5358516
Change-Id: Icae8ef309ea2d89b129f68d30f96b2ca8a69cc6c
This modifies debuggerd to sleep-poll while waiting for the target
process to crash, rather than block (potentially forever).
Also, add/fix some error reporting.
Bug 5035703
Change-Id: Id62ab79f53104927f8de684dff1a5734dbdb8390
When a process receives a fatal signal, it connects to debuggerd
and initiates a conversation over a socket. When the crashing
process is debuggerd, the conversation stalls forever, and you
stop getting native crash details.
This resets the signal handlers to SIG_DFL, so that debuggerd
simply crashes and gets restarted.
Bug 5035703
Change-Id: Ie081d710d046f701bca7e7d8ea3e1d24766d9f61
The delta between start and end pointers in memory dump has to be
multiples of 4 or 16.
Bug: 3486787
Change-Id: Ie34aa79ffb704ca647805dbc6a16f2c35adf849c
The structure user_vfp is incorrectly defined in bionic/libc/kernel/arch-arm/asm/ptrace.h
at the moment, while it should be under bionic/libc/kernel/arch-arm/asm/user.h instead.
Before moving its definition in the corresponding source files, we need to fix its users.
It happens that debuggerd is the only one for now, so fix this by including <linux/user.h>
instead (which will include <asm/user.h> and <asm/ptrace.h>).
Also, make the debug output less chatty by specifying all symbols to be listed
through XLOG2 instead of XLOG.
Change-Id: I16e0fa700945d86efd44ee885a84ad609c0a9b58
This change ensures that debuggered properly releases
the signal handler that invoked it after the PTRACE_ATTACH.
The previous code simply did a close() of the file descriptor,
but for some reason, this didn't always make the read() blocking
the signal handler exit. Instead, the thread would stay blocked
and never fault, preventing the generation of a useful stack
trace.
Change-Id: I6b0579041165a710d74ec1bece113ff7b828aed4
Change 44659e90f (6cc4923087 in AOSP) introduced walking
both the symbol table and dynamic symbol table. The problem
is that it was dereferencing values whether or not the two tables
were both present, which could wind up reading from invalid memory.
The read from a bad address would cause debuggerd itself to crash,
which isn't handled.
Change-Id: Ie936f660018b1980dee5b6ed669588db861f1a79
Change 44659e90f (6cc4923087 in AOSP) introduced walking
both the symbol table and dynamic symbol table. The problem
is that it was dereferencing values whether or not the two tables
were both present, which could wind up reading from invalid memory.
The read from a bad address would cause debuggerd itself to crash,
which isn't handled.
Change-Id: Ie936f660018b1980dee5b6ed669588db861f1a79
Merge commit '5c5ff87ded019537bbaf6383618ef2956aaa0407'
* commit '5c5ff87ded019537bbaf6383618ef2956aaa0407':
Print out the signal code along with signal number and address.
Merge commit '83c6b052918178033875e7ea54ca746cf7303f87' into gingerbread-plus-aosp
* commit '83c6b052918178033875e7ea54ca746cf7303f87':
Print out the signal code along with signal number and address.
Merge commit '891180320f0b08758d053a8562dfcd601ef846b0' into gingerbread-plus-aosp
* commit '891180320f0b08758d053a8562dfcd601ef846b0':
Fix bug in debuggerd so it can successfully find the exidx section in
This change enables debuggerd to provide backtraces with function
names in tombstone files and log messages. It does this by reading
the image file that the address is found in, and parsing the dynamic
symbol table to try to extract the symbol corresponding to the given
address.
This works best when "-Wl,-export-dynamic" is added to the LDFLAGS
of each library and executable, because this will cause all symbols
to be added to the dynamic symbol table. If this flag is not present,
it will still work, but it will only be able to identify functions
which are part of the external API of the library/executable.
Change-Id: I618baaff9ed9143b7d1a1f302224e9f21d2b0626
Changed "process has crashed" message:
- say ":5039" instead of ":port" so mouse-paste of command is trivial
- removed trailing spaces, which consume log buffer to little effect
- improved (I hope) the short explanation of what's going on and
what the HOME key does
Fixed typo ("ignorning").
