[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-15 Thread Pavel Labath via lldb-commits 

https://github.com/labath closed https://github.com/llvm/llvm-project/pull/92093
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[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-15 Thread Pavel Labath via lldb-commits 


@@ -0,0 +1,26 @@
+# REQUIRES: (target-aarch64 || target-arm) && native
+# UNSUPPORTED: system-windows
+
+# RUN: %clang_host %S/Inputs/unaligned-pc-sigbus.c -o %t
+# RUN: %lldb -s %s -o exit %t | FileCheck %s
+
+breakpoint set -n sigbus_handler
+# CHECK: Breakpoint 1: where = {{.*}}`sigbus_handler
+
+run
+# CHECK: thread #1, {{.*}} stop reason = signal SIGBUS

labath wrote:

Thanks for checking this out. I'll xfail the test and reference the rdar, and 
also the llvm bug I created earlier.

https://github.com/llvm/llvm-project/pull/92093
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[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-15 Thread Pavel Labath via lldb-commits 

https://github.com/labath updated 
https://github.com/llvm/llvm-project/pull/92093

>From 391a4129d3da4c4730e50d6ebca23a3c36c3b462 Mon Sep 17 00:00:00 2001
From: Pavel Labath 
Date: Tue, 14 May 2024 01:27:45 -0700
Subject: [PATCH 1/2] [lldb/aarch64] Allow unaligned PC addresses below a trap
 handler

The stack validation heuristic is counter-productive in this case, as
the unaligned address is most likely the thing that caused the signal in
the first place.
---
 lldb/source/Target/UnwindLLDB.cpp |  7 -
 .../Shell/Unwind/Inputs/unaligned-pc-sigbus.c | 21 +++
 .../Shell/Unwind/unaligned-pc-sigbus.test | 26 +++
 3 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c
 create mode 100644 lldb/test/Shell/Unwind/unaligned-pc-sigbus.test

diff --git a/lldb/source/Target/UnwindLLDB.cpp 
b/lldb/source/Target/UnwindLLDB.cpp
index 1d8bf2f88ae67..f43e940492b09 100644
--- a/lldb/source/Target/UnwindLLDB.cpp
+++ b/lldb/source/Target/UnwindLLDB.cpp
@@ -261,7 +261,12 @@ UnwindLLDB::CursorSP UnwindLLDB::GetOneMoreFrame(ABI *abi) 
{
   cur_idx < 100 ? cur_idx : 100, "", cur_idx);
 return nullptr;
   }
-  if (abi && !abi->CodeAddressIsValid(cursor_sp->start_pc)) {
+
+  // Invalid code addresses should not appear on the stack *unless* we're
+  // directly below a trap handler frame (in this case, the invalid address is
+  // likely the cause of the trap).
+  if (abi && !abi->CodeAddressIsValid(cursor_sp->start_pc) &&
+  !prev_frame->reg_ctx_lldb_sp->IsTrapHandlerFrame()) {
 // If the RegisterContextUnwind has a fallback UnwindPlan, it will switch 
to
 // that and return true.  Subsequent calls to TryFallbackUnwindPlan() will
 // return false.
diff --git a/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c 
b/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c
new file mode 100644
index 0..b4818de3b7fb3
--- /dev/null
+++ b/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c
@@ -0,0 +1,21 @@
+#include 
+#include 
+#include 
+
+void sigbus_handler(int signo) { _exit(47); }
+
+int target_function() { return 47; }
+
+int main() {
+  signal(SIGBUS, sigbus_handler);
+
+  // Generate a SIGBUS by deliverately calling through an unaligned function
+  // pointer.
+  union {
+int (*t)();
+uintptr_t p;
+  } u;
+  u.t = target_function;
+  u.p |= 1;
+  return u.t();
+}
diff --git a/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test 
b/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
new file mode 100644
index 0..f74ec1e858551
--- /dev/null
+++ b/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
@@ -0,0 +1,26 @@
+# REQUIRES: (target-aarch64 || target-arm) && native
+# UNSUPPORTED: system-windows
+
+# RUN: %clang_host %S/Inputs/unaligned-pc-sigbus.c -o %t
+# RUN: %lldb -s %s -o exit %t | FileCheck %s
+
+breakpoint set -n sigbus_handler
+# CHECK: Breakpoint 1: where = {{.*}}`sigbus_handler
+
+run
+# CHECK: thread #1, {{.*}} stop reason = signal SIGBUS
+
+thread backtrace
+# CHECK: (lldb) thread backtrace
+# CHECK: frame #0: [[TARGET:0x[0-9a-fA-F]*]] {{.*}}`target_function
+
+continue
+# CHECK: thread #1, {{.*}} stop reason = breakpoint 1
+
+
+thread backtrace
+# CHECK: (lldb) thread backtrace
+# CHECK: frame #0: {{.*}}`sigbus_handler
+# Unknown number of signal trampoline frames
+# CHECK: frame #{{[0-9]+}}: [[TARGET]] {{.*}}`target_function
+

>From b97a7c9752a8ee7e2b5fdcc83790e1bb301f1b42 Mon Sep 17 00:00:00 2001
From: Pavel Labath 
Date: Wed, 15 May 2024 07:58:00 +
Subject: [PATCH 2/2] fix/xfail darwin

---
 lldb/test/Shell/Unwind/unaligned-pc-sigbus.test | 5 +
 1 file changed, 5 insertions(+)

diff --git a/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test 
b/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
index f74ec1e858551..5ebfba54301ef 100644
--- a/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
+++ b/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
@@ -1,9 +1,14 @@
 # REQUIRES: (target-aarch64 || target-arm) && native
 # UNSUPPORTED: system-windows
+# llvm.org/pr91610, rdar://128031075
+# XFAIL: system-darwin
 
 # RUN: %clang_host %S/Inputs/unaligned-pc-sigbus.c -o %t
 # RUN: %lldb -s %s -o exit %t | FileCheck %s
 
+# Convert EXC_BAD_ACCESS into SIGBUS on darwin.
+settings set platform.plugin.darwin.ignored-exceptions EXC_BAD_ACCESS
+
 breakpoint set -n sigbus_handler
 # CHECK: Breakpoint 1: where = {{.*}}`sigbus_handler
 

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[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-14 Thread Jason Molenda via lldb-commits 

https://github.com/jasonmolenda approved this pull request.

Good change, thanks for fixing this.  

https://github.com/llvm/llvm-project/pull/92093
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[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-14 Thread Jason Molenda via lldb-commits 


@@ -0,0 +1,26 @@
+# REQUIRES: (target-aarch64 || target-arm) && native
+# UNSUPPORTED: system-windows
+
+# RUN: %clang_host %S/Inputs/unaligned-pc-sigbus.c -o %t
+# RUN: %lldb -s %s -o exit %t | FileCheck %s
+
+breakpoint set -n sigbus_handler
+# CHECK: Breakpoint 1: where = {{.*}}`sigbus_handler
+
+run
+# CHECK: thread #1, {{.*}} stop reason = signal SIGBUS

jasonmolenda wrote:

Yes doing `b sigbus_handler; r` stops with an EXC_BAD_ACCESS without it being 
delivered to the process. 
`b sigbus_handler; settings set platform.plugin.darwin.ignored-exceptions 
EXC_BAD_ACCESS; r` will stop when the SIGBUS is delivered.  
`b sigbus_handler; settings set platform.plugin.darwin.ignored-exceptions 
EXC_BAD_ACCESS; process handle -p true -s false SIGBUS; r` will stop in 
sigbus_handler.

On macOS we hit the same failure we saw in 
https://github.com/llvm/llvm-project/pull/91321 where we don't have eh_frame 
details for _sigtramp so this frameless leaf function that crashed is not 
discovered when we do the stack walk.  This will need to be xfailed on macOS 
for the same reason as 91321.  FWIW I filed a little work item on myself to 
figure out Something That Can Be Done in rdar://128031075 if you want to 
annotate the xfail.

https://github.com/llvm/llvm-project/pull/92093
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[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-14 Thread Pavel Labath via lldb-commits 


@@ -0,0 +1,26 @@
+# REQUIRES: (target-aarch64 || target-arm) && native
+# UNSUPPORTED: system-windows
+
+# RUN: %clang_host %S/Inputs/unaligned-pc-sigbus.c -o %t
+# RUN: %lldb -s %s -o exit %t | FileCheck %s
+
+breakpoint set -n sigbus_handler
+# CHECK: Breakpoint 1: where = {{.*}}`sigbus_handler
+
+run
+# CHECK: thread #1, {{.*}} stop reason = signal SIGBUS

labath wrote:

I'm guessing I'll also need to forward some mach exception to make this work. 
Would that be EXC_BAD_ACCESS?

https://github.com/llvm/llvm-project/pull/92093
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[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-14 Thread Pavel Labath via lldb-commits 


@@ -0,0 +1,26 @@
+# REQUIRES: (target-aarch64 || target-arm) && native
+# UNSUPPORTED: system-windows
+
+# RUN: %clang_host %S/Inputs/unaligned-pc-sigbus.c -o %t
+# RUN: %lldb -s %s -o exit %t | FileCheck %s
+
+breakpoint set -n sigbus_handler
+# CHECK: Breakpoint 1: where = {{.*}}`sigbus_handler
+
+run
+# CHECK: thread #1, {{.*}} stop reason = signal SIGBUS
+
+thread backtrace
+# CHECK: (lldb) thread backtrace
+# CHECK: frame #0: [[TARGET:0x[0-9a-fA-F]*]] {{.*}}`target_function
+
+continue
+# CHECK: thread #1, {{.*}} stop reason = breakpoint 1
+
+
+thread backtrace
+# CHECK: (lldb) thread backtrace
+# CHECK: frame #0: {{.*}}`sigbus_handler
+# Unknown number of signal trampoline frames
+# CHECK: frame #{{[0-9]+}}: [[TARGET]] {{.*}}`target_function

labath wrote:

This will currently not unwind past the `target_function` without the fix in 
#91321

https://github.com/llvm/llvm-project/pull/92093
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[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-14 Thread via lldb-commits 

llvmbot wrote:




@llvm/pr-subscribers-lldb

Author: Pavel Labath (labath)


Changes

The stack validation heuristic is counter-productive in this case, as the 
unaligned address is most likely the thing that caused the signal in the first 
place.

---
Full diff: https://github.com/llvm/llvm-project/pull/92093.diff


3 Files Affected:

- (modified) lldb/source/Target/UnwindLLDB.cpp (+6-1) 
- (added) lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c (+21) 
- (added) lldb/test/Shell/Unwind/unaligned-pc-sigbus.test (+26) 


``diff
diff --git a/lldb/source/Target/UnwindLLDB.cpp 
b/lldb/source/Target/UnwindLLDB.cpp
index 1d8bf2f88ae67..f43e940492b09 100644
--- a/lldb/source/Target/UnwindLLDB.cpp
+++ b/lldb/source/Target/UnwindLLDB.cpp
@@ -261,7 +261,12 @@ UnwindLLDB::CursorSP UnwindLLDB::GetOneMoreFrame(ABI *abi) 
{
   cur_idx < 100 ? cur_idx : 100, "", cur_idx);
 return nullptr;
   }
-  if (abi && !abi->CodeAddressIsValid(cursor_sp->start_pc)) {
+
+  // Invalid code addresses should not appear on the stack *unless* we're
+  // directly below a trap handler frame (in this case, the invalid address is
+  // likely the cause of the trap).
+  if (abi && !abi->CodeAddressIsValid(cursor_sp->start_pc) &&
+  !prev_frame->reg_ctx_lldb_sp->IsTrapHandlerFrame()) {
 // If the RegisterContextUnwind has a fallback UnwindPlan, it will switch 
to
 // that and return true.  Subsequent calls to TryFallbackUnwindPlan() will
 // return false.
diff --git a/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c 
b/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c
new file mode 100644
index 0..b4818de3b7fb3
--- /dev/null
+++ b/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c
@@ -0,0 +1,21 @@
+#include 
+#include 
+#include 
+
+void sigbus_handler(int signo) { _exit(47); }
+
+int target_function() { return 47; }
+
+int main() {
+  signal(SIGBUS, sigbus_handler);
+
+  // Generate a SIGBUS by deliverately calling through an unaligned function
+  // pointer.
+  union {
+int (*t)();
+uintptr_t p;
+  } u;
+  u.t = target_function;
+  u.p |= 1;
+  return u.t();
+}
diff --git a/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test 
b/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
new file mode 100644
index 0..f74ec1e858551
--- /dev/null
+++ b/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
@@ -0,0 +1,26 @@
+# REQUIRES: (target-aarch64 || target-arm) && native
+# UNSUPPORTED: system-windows
+
+# RUN: %clang_host %S/Inputs/unaligned-pc-sigbus.c -o %t
+# RUN: %lldb -s %s -o exit %t | FileCheck %s
+
+breakpoint set -n sigbus_handler
+# CHECK: Breakpoint 1: where = {{.*}}`sigbus_handler
+
+run
+# CHECK: thread #1, {{.*}} stop reason = signal SIGBUS
+
+thread backtrace
+# CHECK: (lldb) thread backtrace
+# CHECK: frame #0: [[TARGET:0x[0-9a-fA-F]*]] {{.*}}`target_function
+
+continue
+# CHECK: thread #1, {{.*}} stop reason = breakpoint 1
+
+
+thread backtrace
+# CHECK: (lldb) thread backtrace
+# CHECK: frame #0: {{.*}}`sigbus_handler
+# Unknown number of signal trampoline frames
+# CHECK: frame #{{[0-9]+}}: [[TARGET]] {{.*}}`target_function
+

``




https://github.com/llvm/llvm-project/pull/92093
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[Lldb-commits] [lldb] [lldb/aarch64] Allow unaligned PC addresses below a trap handler (PR #92093)

2024-05-14 Thread Pavel Labath via lldb-commits 

https://github.com/labath created 
https://github.com/llvm/llvm-project/pull/92093

The stack validation heuristic is counter-productive in this case, as the 
unaligned address is most likely the thing that caused the signal in the first 
place.

>From 391a4129d3da4c4730e50d6ebca23a3c36c3b462 Mon Sep 17 00:00:00 2001
From: Pavel Labath 
Date: Tue, 14 May 2024 01:27:45 -0700
Subject: [PATCH] [lldb/aarch64] Allow unaligned PC addresses below a trap
 handler

The stack validation heuristic is counter-productive in this case, as
the unaligned address is most likely the thing that caused the signal in
the first place.
---
 lldb/source/Target/UnwindLLDB.cpp |  7 -
 .../Shell/Unwind/Inputs/unaligned-pc-sigbus.c | 21 +++
 .../Shell/Unwind/unaligned-pc-sigbus.test | 26 +++
 3 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c
 create mode 100644 lldb/test/Shell/Unwind/unaligned-pc-sigbus.test

diff --git a/lldb/source/Target/UnwindLLDB.cpp 
b/lldb/source/Target/UnwindLLDB.cpp
index 1d8bf2f88ae67..f43e940492b09 100644
--- a/lldb/source/Target/UnwindLLDB.cpp
+++ b/lldb/source/Target/UnwindLLDB.cpp
@@ -261,7 +261,12 @@ UnwindLLDB::CursorSP UnwindLLDB::GetOneMoreFrame(ABI *abi) 
{
   cur_idx < 100 ? cur_idx : 100, "", cur_idx);
 return nullptr;
   }
-  if (abi && !abi->CodeAddressIsValid(cursor_sp->start_pc)) {
+
+  // Invalid code addresses should not appear on the stack *unless* we're
+  // directly below a trap handler frame (in this case, the invalid address is
+  // likely the cause of the trap).
+  if (abi && !abi->CodeAddressIsValid(cursor_sp->start_pc) &&
+  !prev_frame->reg_ctx_lldb_sp->IsTrapHandlerFrame()) {
 // If the RegisterContextUnwind has a fallback UnwindPlan, it will switch 
to
 // that and return true.  Subsequent calls to TryFallbackUnwindPlan() will
 // return false.
diff --git a/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c 
b/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c
new file mode 100644
index 0..b4818de3b7fb3
--- /dev/null
+++ b/lldb/test/Shell/Unwind/Inputs/unaligned-pc-sigbus.c
@@ -0,0 +1,21 @@
+#include 
+#include 
+#include 
+
+void sigbus_handler(int signo) { _exit(47); }
+
+int target_function() { return 47; }
+
+int main() {
+  signal(SIGBUS, sigbus_handler);
+
+  // Generate a SIGBUS by deliverately calling through an unaligned function
+  // pointer.
+  union {
+int (*t)();
+uintptr_t p;
+  } u;
+  u.t = target_function;
+  u.p |= 1;
+  return u.t();
+}
diff --git a/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test 
b/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
new file mode 100644
index 0..f74ec1e858551
--- /dev/null
+++ b/lldb/test/Shell/Unwind/unaligned-pc-sigbus.test
@@ -0,0 +1,26 @@
+# REQUIRES: (target-aarch64 || target-arm) && native
+# UNSUPPORTED: system-windows
+
+# RUN: %clang_host %S/Inputs/unaligned-pc-sigbus.c -o %t
+# RUN: %lldb -s %s -o exit %t | FileCheck %s
+
+breakpoint set -n sigbus_handler
+# CHECK: Breakpoint 1: where = {{.*}}`sigbus_handler
+
+run
+# CHECK: thread #1, {{.*}} stop reason = signal SIGBUS
+
+thread backtrace
+# CHECK: (lldb) thread backtrace
+# CHECK: frame #0: [[TARGET:0x[0-9a-fA-F]*]] {{.*}}`target_function
+
+continue
+# CHECK: thread #1, {{.*}} stop reason = breakpoint 1
+
+
+thread backtrace
+# CHECK: (lldb) thread backtrace
+# CHECK: frame #0: {{.*}}`sigbus_handler
+# Unknown number of signal trampoline frames
+# CHECK: frame #{{[0-9]+}}: [[TARGET]] {{.*}}`target_function
+

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