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Fix native frame unwind in syscall on arm64 for VS4Mac crash report. #63598

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merged 3 commits into from
Jan 13, 2022

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@mikem8361 mikem8361 commented Jan 10, 2022

Add arm64 version of StepWithCompactNoEncoding for syscall leaf node wrappers that have compact encoding of 0.

Fix ReadCompactEncodingRegister so it actually decrements the addr.

Change StepWithCompactEncodingArm64 to match what MacOS libunwind does for framed and frameless stepping.

arm64 can have frames with the same SP (but different IPs). Increment SP for this condition so createdump's unwind
loop doesn't break out on the "SP not increasing" check and the frames are added to the thread frame list in the
correct order.

Add getting the unwind info for tail called functions like this:

__ZL14PROCEndProcessPvji:
   36630:       f6 57 bd a9     stp     x22, x21, [sp, #-48]!
   36634:       f4 4f 01 a9     stp     x20, x19, [sp, #16]
   36638:       fd 7b 02 a9     stp     x29, x30, [sp, #32]
   3663c:       fd 83 00 91     add     x29, sp, #32
...
   367ac:       e9 01 80 52     mov     w9, #15
   367b0:       7f 3e 02 71     cmp     w19, #143
   367b4:       20 01 88 1a     csel    w0, w9, w8, eq
   367b8:       2e 00 00 94     bl      _PROCAbort
_TerminateProcess:
-> 367bc:       22 00 80 52     mov     w2, #1
   367c0:       9c ff ff 17     b       __ZL14PROCEndProcessPvji

The IP (367bc) returns the (incorrect) frameless encoding with nothing on the stack (uses an incorrect LR to unwind). To fix this
get the unwind info for PC -1 which points to PROCEndProcess with the correct unwind info. This matches how lldb unwinds this frame.

Always address module segment to IP lookup list instead of checking the module regions.

Strip pointer authentication bits on PC/LR.

Add arm64 version of StepWithCompactNoEncoding for syscall leaf node wrappers that have compact encoding of 0.

Fix ReadCompactEncodingRegister so it actually decrements the addr.

Change StepWithCompactEncodingArm64 to match what MacOS libunwind does for framed and frameless stepping.

arm64 can have frames with the same SP (but different IPs). Increment SP for this condition so createdump's unwind
loop doesn't break out on the "SP not increasing" check and the frames are added to the thread frame list in the
correct order.

Add getting the unwind info for tail called functions like this:

__ZL14PROCEndProcessPvji:
   36630:       f6 57 bd a9     stp     x22, x21, [sp, #-48]!
   36634:       f4 4f 01 a9     stp     x20, x19, [sp, dotnet#16]
   36638:       fd 7b 02 a9     stp     x29, x30, [sp, dotnet#32]
   3663c:       fd 83 00 91     add     x29, sp, dotnet#32
...
   367ac:       e9 01 80 52     mov     w9, dotnet#15
   367b0:       7f 3e 02 71     cmp     w19, dotnet#143
   367b4:       20 01 88 1a     csel    w0, w9, w8, eq
   367b8:       2e 00 00 94     bl      _PROCAbort
_TerminateProcess:
-> 367bc:       22 00 80 52     mov     w2, dotnet#1
   367c0:       9c ff ff 17     b       __ZL14PROCEndProcessPvji

The IP (367bc) returns the (incorrect) frameless encoding with nothing on the stack (uses an incorrect LR to unwind). To fix this
get the unwind info for PC -1 which points to PROCEndProcess with the correct unwind info. This matches how lldb unwinds this frame.

Always address module segment to IP lookup list instead of checking the module regions.

Strip pointer authentication bits on PC/LR.
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Issue Details

Add arm64 version of StepWithCompactNoEncoding for syscall leaf node wrappers that have compact encoding of 0.

Fix ReadCompactEncodingRegister so it actually decrements the addr.

Change StepWithCompactEncodingArm64 to match what MacOS libunwind does for framed and frameless stepping.

arm64 can have frames with the same SP (but different IPs). Increment SP for this condition so createdump's unwind
loop doesn't break out on the "SP not increasing" check and the frames are added to the thread frame list in the
correct order.

Add getting the unwind info for tail called functions like this:

__ZL14PROCEndProcessPvji:
36630: f6 57 bd a9 stp x22, x21, [sp, #-48]!
36634: f4 4f 01 a9 stp x20, x19, [sp, #16]
36638: fd 7b 02 a9 stp x29, x30, [sp, #32]
3663c: fd 83 00 91 add x29, sp, #32
...
367ac: e9 01 80 52 mov w9, #15
367b0: 7f 3e 02 71 cmp w19, #143
367b4: 20 01 88 1a csel w0, w9, w8, eq
367b8: 2e 00 00 94 bl _PROCAbort
_TerminateProcess:
-> 367bc: 22 00 80 52 mov w2, #1
367c0: 9c ff ff 17 b __ZL14PROCEndProcessPvji

The IP (367bc) returns the (incorrect) frameless encoding with nothing on the stack (uses an incorrect LR to unwind). To fix this
get the unwind info for PC -1 which points to PROCEndProcess with the correct unwind info. This matches how lldb unwinds this frame.

Always address module segment to IP lookup list instead of checking the module regions.

Strip pointer authentication bits on PC/LR.

Author: mikem8361
Assignees: mikem8361
Labels:

area-Diagnostics-coreclr

Milestone: -

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@kdubau

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@hoyosjs hoyosjs left a comment

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The BL/BLR part looks correct now in comparison to the armv8 manual. I see a failure though with an assert in libunwind on linux arm64 that seems like it could be related to this.

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LGTM, thank you!

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I see a failure though with an assert in libunwind on linux arm64 that seems like it could be related to this.

It would be worth looking at it, there is a dump in the test results. @mikem8361 I can take a look if you want.

@mikem8361 mikem8361 merged commit dc67c70 into dotnet:main Jan 13, 2022
@mikem8361 mikem8361 deleted the arm64unwind branch January 13, 2022 00:00
mikem8361 added a commit to mikem8361/runtime that referenced this pull request Jan 13, 2022
From PR in main: dotnet#63598

Add arm64 version of StepWithCompactNoEncoding for syscall leaf node wrappers that have compact encoding of 0.

Fix ReadCompactEncodingRegister so it actually decrements the addr.

Change StepWithCompactEncodingArm64 to match what MacOS libunwind does for framed and frameless stepping.

arm64 can have frames with the same SP (but different IPs). Increment SP for this condition so createdump's unwind
loop doesn't break out on the "SP not increasing" check and the frames are added to the thread frame list in the
correct order.

Add getting the unwind info for tail called functions like this:

__ZL14PROCEndProcessPvji:
   36630:       f6 57 bd a9     stp     x22, x21, [sp, #-48]!
   36634:       f4 4f 01 a9     stp     x20, x19, [sp, dotnet#16]
   36638:       fd 7b 02 a9     stp     x29, x30, [sp, dotnet#32]
   3663c:       fd 83 00 91     add     x29, sp, dotnet#32
...
   367ac:       e9 01 80 52     mov     w9, dotnet#15
   367b0:       7f 3e 02 71     cmp     w19, dotnet#143
   367b4:       20 01 88 1a     csel    w0, w9, w8, eq
   367b8:       2e 00 00 94     bl      _PROCAbort
_TerminateProcess:
-> 367bc:       22 00 80 52     mov     w2, dotnet#1
   367c0:       9c ff ff 17     b       __ZL14PROCEndProcessPvji

The IP (367bc) returns the (incorrect) frameless encoding with nothing on the stack (uses an incorrect LR to unwind). To fix this
get the unwind info for PC -1 which points to PROCEndProcess with the correct unwind info. This matches how lldb unwinds this frame.

Always address module segment to IP lookup list instead of checking the module regions.

Strip pointer authentication bits on PC/LR.
agocke added a commit that referenced this pull request Jan 13, 2022
jeffschwMSFT pushed a commit that referenced this pull request Jan 13, 2022
* Fix the MacOS remote unwinder for VS4Mac

The wrong module was being passed to the remote unwinder because the load bias for shared modules
was being calculated incorrectly.

Issue: #63309

* Fix native frame unwind in syscall on arm64 for VS4Mac crash report

From PR in main: #63598

Add arm64 version of StepWithCompactNoEncoding for syscall leaf node wrappers that have compact encoding of 0.

Fix ReadCompactEncodingRegister so it actually decrements the addr.

Change StepWithCompactEncodingArm64 to match what MacOS libunwind does for framed and frameless stepping.

arm64 can have frames with the same SP (but different IPs). Increment SP for this condition so createdump's unwind
loop doesn't break out on the "SP not increasing" check and the frames are added to the thread frame list in the
correct order.

Add getting the unwind info for tail called functions like this:

__ZL14PROCEndProcessPvji:
   36630:       f6 57 bd a9     stp     x22, x21, [sp, #-48]!
   36634:       f4 4f 01 a9     stp     x20, x19, [sp, #16]
   36638:       fd 7b 02 a9     stp     x29, x30, [sp, #32]
   3663c:       fd 83 00 91     add     x29, sp, #32
...
   367ac:       e9 01 80 52     mov     w9, #15
   367b0:       7f 3e 02 71     cmp     w19, #143
   367b4:       20 01 88 1a     csel    w0, w9, w8, eq
   367b8:       2e 00 00 94     bl      _PROCAbort
_TerminateProcess:
-> 367bc:       22 00 80 52     mov     w2, #1
   367c0:       9c ff ff 17     b       __ZL14PROCEndProcessPvji

The IP (367bc) returns the (incorrect) frameless encoding with nothing on the stack (uses an incorrect LR to unwind). To fix this
get the unwind info for PC -1 which points to PROCEndProcess with the correct unwind info. This matches how lldb unwinds this frame.

Always address module segment to IP lookup list instead of checking the module regions.

Strip pointer authentication bits on PC/LR.
github-actions bot pushed a commit that referenced this pull request Jan 13, 2022
From PR in main: #63598

Add arm64 version of StepWithCompactNoEncoding for syscall leaf node wrappers that have compact encoding of 0.

Fix ReadCompactEncodingRegister so it actually decrements the addr.

Change StepWithCompactEncodingArm64 to match what MacOS libunwind does for framed and frameless stepping.

arm64 can have frames with the same SP (but different IPs). Increment SP for this condition so createdump's unwind
loop doesn't break out on the "SP not increasing" check and the frames are added to the thread frame list in the
correct order.

Add getting the unwind info for tail called functions like this:

__ZL14PROCEndProcessPvji:
   36630:       f6 57 bd a9     stp     x22, x21, [sp, #-48]!
   36634:       f4 4f 01 a9     stp     x20, x19, [sp, #16]
   36638:       fd 7b 02 a9     stp     x29, x30, [sp, #32]
   3663c:       fd 83 00 91     add     x29, sp, #32
...
   367ac:       e9 01 80 52     mov     w9, #15
   367b0:       7f 3e 02 71     cmp     w19, #143
   367b4:       20 01 88 1a     csel    w0, w9, w8, eq
   367b8:       2e 00 00 94     bl      _PROCAbort
_TerminateProcess:
-> 367bc:       22 00 80 52     mov     w2, #1
   367c0:       9c ff ff 17     b       __ZL14PROCEndProcessPvji

The IP (367bc) returns the (incorrect) frameless encoding with nothing on the stack (uses an incorrect LR to unwind). To fix this
get the unwind info for PC -1 which points to PROCEndProcess with the correct unwind info. This matches how lldb unwinds this frame.

Always address module segment to IP lookup list instead of checking the module regions.

Strip pointer authentication bits on PC/LR.
safern pushed a commit that referenced this pull request Jan 13, 2022
* Fix the MacOS remote unwinder for VS4Mac

The wrong module was being passed to the remote unwinder because the load bias for shared modules
was being calculated incorrectly.

Issue: #63309

* Fix native frame unwind in syscall on arm64 for VS4Mac crash report

From PR in main: #63598

Add arm64 version of StepWithCompactNoEncoding for syscall leaf node wrappers that have compact encoding of 0.

Fix ReadCompactEncodingRegister so it actually decrements the addr.

Change StepWithCompactEncodingArm64 to match what MacOS libunwind does for framed and frameless stepping.

arm64 can have frames with the same SP (but different IPs). Increment SP for this condition so createdump's unwind
loop doesn't break out on the "SP not increasing" check and the frames are added to the thread frame list in the
correct order.

Add getting the unwind info for tail called functions like this:

__ZL14PROCEndProcessPvji:
   36630:       f6 57 bd a9     stp     x22, x21, [sp, #-48]!
   36634:       f4 4f 01 a9     stp     x20, x19, [sp, #16]
   36638:       fd 7b 02 a9     stp     x29, x30, [sp, #32]
   3663c:       fd 83 00 91     add     x29, sp, #32
...
   367ac:       e9 01 80 52     mov     w9, #15
   367b0:       7f 3e 02 71     cmp     w19, #143
   367b4:       20 01 88 1a     csel    w0, w9, w8, eq
   367b8:       2e 00 00 94     bl      _PROCAbort
_TerminateProcess:
-> 367bc:       22 00 80 52     mov     w2, #1
   367c0:       9c ff ff 17     b       __ZL14PROCEndProcessPvji

The IP (367bc) returns the (incorrect) frameless encoding with nothing on the stack (uses an incorrect LR to unwind). To fix this
get the unwind info for PC -1 which points to PROCEndProcess with the correct unwind info. This matches how lldb unwinds this frame.

Always address module segment to IP lookup list instead of checking the module regions.

Strip pointer authentication bits on PC/LR.

Co-authored-by: Mike McLaughlin <mikem@microsoft.com>
@ghost ghost locked as resolved and limited conversation to collaborators Feb 12, 2022
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