Stream: git-wasmtime

Topic: wasmtime / issue #11489 Exceptions: dynamic context load ...

view this post on Zulip Wasmtime GitHub notifications bot (Aug 21 2025 at 17:08):

cfallin edited issue #11489:

Test Case

bug.zip

Steps to Reproduce

Run the following command:

./target/debug/wasmtime  -W=all-proposals=y bug.wasm

Expected Results

It should not crash

Actual Results

I get a segfault

Versions and Environment

Wasmtime commit: 2d25f862b38abd484e5418327a9149e69d3274aa

Operating system: Linux

Architecture: x64

Extra Info

I suspect that the stack unwinder does not deal properly with tail calls.

I get the following stack trace in gdb:

#0  wasmtime::runtime::vm::ModuleRuntimeInfo::env_module (self=0x7ffeffffff68)
    at crates/wasmtime/src/runtime/vm.rs:329
#1  0x0000555557fd524f in wasmtime::runtime::vm::instance::Instance::env_module
    (self=0x7ffeffffff60) at crates/wasmtime/src/runtime/vm/instance.rs:357
#2  0x0000555557fd5fe8 in wasmtime::runtime::vm::instance::Instance::get_exported_tag (self=0x7ffeffffff60, store=..., index=...)
    at crates/wasmtime/src/runtime/vm/instance.rs:666
#3  0x0000555557fb4cad in wasmtime::runtime::vm::throw::compute_throw_action::{closure#0} (frame=0x7ffff69f48f0) at crates/wasmtime/src/runtime/vm/throw.rs:98
#4  0x0000555557f12e5e in wasmtime_internal_unwinder::throw::compute_throw_action::{closure#0}<wasmtime::runtime::vm::throw::compute_throw_action::{closure_env#0}> (frame=...) at crates/unwinder/src/throw.rs:76
#5  0x0000555558034d24 in wasmtime_internal_unwinder::stackwalk::visit_frames<wasmtime_internal_unwinder::throw::ThrowAction, wasmtime_internal_unwinder::throw::compute_throw_action::{closure_env#0}<wasmtime::runtime::vm::throw::compute_throw_action::{closure_env#0}>> (unwind=..., pc=140737353797698,
    fp=140737331026544, trampoline_fp=140737331026560, f=...)
    at crates/unwinder/src/stackwalk.rs:203
#6  0x0000555557f12c31 in wasmtime_internal_unwinder::throw::compute_throw_action<wasmtime::runtime::vm::throw::compute_throw_action::{closure_env#0}> (
    unwind=..., frame_handler=..., exit_pc=140737353797991,
    exit_trampoline_frame=140737331026368, entry_frame=140737331026560)
    at crates/unwinder/src/throw.rs:60
--Type <RET> for more, q to quit, c to continue without paging--
#7  0x0000555557da8980 in wasmtime::runtime::vm::throw::compute_throw_action (
    store=...) at crates/wasmtime/src/runtime/vm/throw.rs:120
#8  0x0000555557be3f0a in wasmtime::runtime::vm::traphandlers::call_thread_state::CallThreadState::record_unwind (self=0x7ffff69f5f30, store=..., reason=...)
    at crates/wasmtime/src/runtime/vm/traphandlers.rs:819
#9  0x0000555558088a8b in wasmtime::runtime::vm::traphandlers::catch_unwind_and_record_trap::{closure#1}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::instance::{impl#0}::enter_host_from_wasm::{closure_env#0}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::libcalls::raw::throw_ref::{closure_env#0}>> (info=...) at crates/wasmtime/src/runtime/vm/traphandlers.rs:136
#10 0x0000555557eff1ef in wasmtime::runtime::vm::traphandlers::tls::with<(), wasmtime::runtime::vm::traphandlers::catch_unwind_and_record_trap::{closure_env#1}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::instance::{impl#0}::enter_host_from_wasm::{closure_env#0}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::libcalls::raw::throw_ref::{closure_env#0}>>> (closure=...)
    at crates/wasmtime/src/runtime/vm/traphandlers.rs:1394
#11 0x0000555558084079 in wasmtime::runtime::vm::traphandlers::catch_unwind_and_record_trap<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::instance::{impl#0}::enter_host_from_wasm::{closure_env#0}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::libcalls::raw::throw_ref::{closure_env#0}>> (
    store=..., f=...) at crates/wasmtime/src/runtime/vm/traphandlers.rs:136
#12 0x0000555557c650b2 in wasmtime::runtime::vm::instance::Instance::enter_host_from_wasm<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::libcalls::raw::throw_ref::{closure_env#0}> (
    vmctx=..., f=...) at crates/wasmtime/src/runtime/vm/instance.rs:265
#13 0x0000555557f6b0bb in wasmtime::runtime::vm::libcalls::raw::throw_ref (
    vmctx=..., exnref=16) at crates/wasmtime/src/runtime/vm/libcalls.rs:125

view this post on Zulip Wasmtime GitHub notifications bot (Aug 21 2025 at 17:28):

cfallin commented on issue #11489:

Ah, actually, we need the SP anyway in order to actually resume to that frame -- so we need some metadata in the exception table indicating the size of the stack frame (SP offset downward from FP). No worries, I think we can do that.

view this post on Zulip Wasmtime GitHub notifications bot (Aug 21 2025 at 21:17):

cfallin commented on issue #11489:

I have a working fix on x86-64 (and also tested on aarch64) in this branch but I'm debugging s390x right now -- it's a bit different due to its use of SP backchains (which we treat as almost an FP).

view this post on Zulip Wasmtime GitHub notifications bot (Aug 21 2025 at 23:10):

alexcrichton closed issue #11489:

Test Case

bug.zip

Steps to Reproduce

Run the following command:

./target/debug/wasmtime  -W=all-proposals=y bug.wasm

Expected Results

It should not crash

Actual Results

I get a segfault

Versions and Environment

Wasmtime commit: 2d25f862b38abd484e5418327a9149e69d3274aa

Operating system: Linux

Architecture: x64

Extra Info

I suspect that the stack unwinder does not deal properly with tail calls.

I get the following stack trace in gdb:

#0  wasmtime::runtime::vm::ModuleRuntimeInfo::env_module (self=0x7ffeffffff68)
    at crates/wasmtime/src/runtime/vm.rs:329
#1  0x0000555557fd524f in wasmtime::runtime::vm::instance::Instance::env_module
    (self=0x7ffeffffff60) at crates/wasmtime/src/runtime/vm/instance.rs:357
#2  0x0000555557fd5fe8 in wasmtime::runtime::vm::instance::Instance::get_exported_tag (self=0x7ffeffffff60, store=..., index=...)
    at crates/wasmtime/src/runtime/vm/instance.rs:666
#3  0x0000555557fb4cad in wasmtime::runtime::vm::throw::compute_throw_action::{closure#0} (frame=0x7ffff69f48f0) at crates/wasmtime/src/runtime/vm/throw.rs:98
#4  0x0000555557f12e5e in wasmtime_internal_unwinder::throw::compute_throw_action::{closure#0}<wasmtime::runtime::vm::throw::compute_throw_action::{closure_env#0}> (frame=...) at crates/unwinder/src/throw.rs:76
#5  0x0000555558034d24 in wasmtime_internal_unwinder::stackwalk::visit_frames<wasmtime_internal_unwinder::throw::ThrowAction, wasmtime_internal_unwinder::throw::compute_throw_action::{closure_env#0}<wasmtime::runtime::vm::throw::compute_throw_action::{closure_env#0}>> (unwind=..., pc=140737353797698,
    fp=140737331026544, trampoline_fp=140737331026560, f=...)
    at crates/unwinder/src/stackwalk.rs:203
#6  0x0000555557f12c31 in wasmtime_internal_unwinder::throw::compute_throw_action<wasmtime::runtime::vm::throw::compute_throw_action::{closure_env#0}> (
    unwind=..., frame_handler=..., exit_pc=140737353797991,
    exit_trampoline_frame=140737331026368, entry_frame=140737331026560)
    at crates/unwinder/src/throw.rs:60
--Type <RET> for more, q to quit, c to continue without paging--
#7  0x0000555557da8980 in wasmtime::runtime::vm::throw::compute_throw_action (
    store=...) at crates/wasmtime/src/runtime/vm/throw.rs:120
#8  0x0000555557be3f0a in wasmtime::runtime::vm::traphandlers::call_thread_state::CallThreadState::record_unwind (self=0x7ffff69f5f30, store=..., reason=...)
    at crates/wasmtime/src/runtime/vm/traphandlers.rs:819
#9  0x0000555558088a8b in wasmtime::runtime::vm::traphandlers::catch_unwind_and_record_trap::{closure#1}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::instance::{impl#0}::enter_host_from_wasm::{closure_env#0}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::libcalls::raw::throw_ref::{closure_env#0}>> (info=...) at crates/wasmtime/src/runtime/vm/traphandlers.rs:136
#10 0x0000555557eff1ef in wasmtime::runtime::vm::traphandlers::tls::with<(), wasmtime::runtime::vm::traphandlers::catch_unwind_and_record_trap::{closure_env#1}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::instance::{impl#0}::enter_host_from_wasm::{closure_env#0}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::libcalls::raw::throw_ref::{closure_env#0}>>> (closure=...)
    at crates/wasmtime/src/runtime/vm/traphandlers.rs:1394
#11 0x0000555558084079 in wasmtime::runtime::vm::traphandlers::catch_unwind_and_record_trap<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::instance::{impl#0}::enter_host_from_wasm::{closure_env#0}<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::libcalls::raw::throw_ref::{closure_env#0}>> (
    store=..., f=...) at crates/wasmtime/src/runtime/vm/traphandlers.rs:136
#12 0x0000555557c650b2 in wasmtime::runtime::vm::instance::Instance::enter_host_from_wasm<core::result::Result<(), wasmtime::runtime::vm::traphandlers::TrapReason>, wasmtime::runtime::vm::libcalls::raw::throw_ref::{closure_env#0}> (
    vmctx=..., f=...) at crates/wasmtime/src/runtime/vm/instance.rs:265
#13 0x0000555557f6b0bb in wasmtime::runtime::vm::libcalls::raw::throw_ref (
    vmctx=..., exnref=16) at crates/wasmtime/src/runtime/vm/libcalls.rs:125

Last updated: Dec 06 2025 at 07:03 UTC