[Lldb-commits] [PATCH] D105180: [lldb][AArch64] Add memory tag writing to lldb-server

[Muhammad Omair Javaid via Phabricator via lldb-commits]

omjavaid added inline comments.


================
Comment at: lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp:1550
+    size_t tags_written = tags_vec.iov_len;
+    assert(tags_written && (tags_written <= num_tags));
+
----------------
This assertion suggests something went wrong on ptrace side. Should we replace it with a simple error return? or you think inferior program should no longer be debugable after such an error?


================
Comment at: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp:3567
+
+  // This is bytes here and is unpacked into target specific tags later
+  // We cannot assume that number of bytes == length here because the server
----------------
by this you mean packet?


================
Comment at: lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py:56
         # Run the packet stream
         context = self.expect_gdbremote_sequence()
         self.assertIsNotNone(context)
----------------
DavidSpickett wrote:
> omjavaid wrote:
> > This test is still not stable given we wait for stop notification while process may have exited. This causes test to hang till timeout expiry.
> Sure, but I don't think there's a better way to do it. Short of reading from a process that's already exited. (which seems to sort of work for memory but tags have weird results so I don't think it's meant to work)
> 
> Note that the test file does pause after the print: https://github.com/llvm/llvm-project/blob/main/lldb/test/API/tools/lldb-server/memory-tagging/main.c#L16
> 
> We've got a few scenarios:
> * All goes well, we get the print. The test program is in it's delay and we stop it.
> * The test crashes at some point before sending the stop. The test program waits 60s then exits.
> * The test program crashes before printing. The test waits on the print until it times out.
> * The test picks up the print just as the test program is exiting, or has already exited. The test times out waiting for the stop response.
> 
> It's not free of timing issues but it means that you won't have either test or test program hanging around if either fails.
> 
> What do you think?
The problem I was facing was lldb-server existed after inferior launch. I have given my configuration below I might be doing something wrong:
LLDB_TEST_COMPILER=/home/omair/work/tools/gcc-linaro-11.0.0-2021.02-x86_64_aarch64-linux-gnu/bin/aarch64-linux-gnu-gcc
LLDB_TEST_ARCH=aarch64

LLDB_PLATFORM_NAME=remote-linux
LLDB_PLATFORM_URL=connect://192.168.53.253:54321
#-u CXXFLAGS -u CFLAGS --env ARCHIVER=/usr/bin/ar --env OBJCOPY=/usr/bin/objcopy \

$LLDB_BUILD_DIR/bin/lldb-dotest \
-A $LLDB_TEST_ARCH \
-C $LLDB_TEST_COMPILER \
--build-dir $LLDB_BUILD_DIR/lldb-test-build.noindex \
--executable $LLDB_BUILD_DIR/bin/lldb \
--dsymutil $LLDB_BUILD_DIR/bin/dsymutil \
--llvm-tools-dir $LLDB_BUILD_DIR/bin \
--lldb-libs-dir $LLDB_BUILD_DIR/lib \
--platform-name=$LLDB_PLATFORM_NAME \
--platform-url=$LLDB_PLATFORM_URL \
-p $1 $2 $3



Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D105180/new/

https://reviews.llvm.org/D105180