iced: Asan finds memory leaks.

I noticed this when my project’s CI failed after using iced_x86 for the first time.

If you run the Rust test suite with Asan enabled, there are a lot of leaks reported. e.g.:

$ ASAN_SYMBOLIZER_PATH=/usr/bin/llvm-symbolizer-15 RUSTFLAGS="-Z sanitizer=address" cargo test --lib -Z build-std --target x86_64-unknown-linux-gnu
...
Direct leak of 7608 byte(s) in 317 object(s) allocated from:                                                                                                                                                                                  
    #0 0x564d04b1c0ef in malloc /rustc/llvm/src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:68:3                                                                                                                                  
    #1 0x564d0643799b in std::sys::pal::unix::alloc::_$LT$impl$u20$core..alloc..global..GlobalAlloc$u20$for$u20$std..alloc..System$GT$::alloc::h06dd0a20178c9edd /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/
src/rust/library/std/src/sys/pal/unix/alloc.rs:14:13                                                                                                                                                                                          
    #2 0x564d065e833c in __rdl_alloc /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/alloc.rs:394:13                                                                                    
    #3 0x564d05d989e4 in alloc::alloc::Global::alloc_impl::h07a2feba7ca619c8 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:181:73                                          
    #4 0x564d05d99658 in _$LT$alloc..alloc..Global$u20$as$u20$core..alloc..Allocator$GT$::allocate::h61e7f0c3f82e9586 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:241:9  
    #5 0x564d059717c5 in _$LT$iced_x86..formatter..fast..fmt_tbl..FMT_DATA$u20$as$u20$core..ops..deref..Deref$GT$::deref::__static_ref_initialize::hf4d827215169b2b4 /home/vext01/source/iced/src/rust/iced-x86/src/formatter/fast/fmt_tbl.rs:
20:49                                                                                                                                                                                                                                         
    #6 0x564d059717c5 in core::ops::function::FnOnce::call_once::hfa5fc15e22c577d4 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5                               
    #7 0x564d05f6d045 in std::sync::once::Once::call_once::he6f6c46da8d6d107 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/once.rs:149:9                                         
    #8 0x564d059c99a7 in lazy_static::lazy::Lazy$LT$T$GT$::get::h0abcb01fa137bc7b /home/vext01/.cargo/registry/src/index.crates.io-6f17d22bba15001f/lazy_static-1.4.0/src/inline_lazy.rs:30:9                                                 
    #9 0x564d059c99a7 in _$LT$iced_x86..formatter..fast..fmt_tbl..FMT_DATA$u20$as$u20$core..ops..deref..Deref$GT$::deref::__stability::ha0ac771135e86dd9 /home/vext01/.cargo/registry/src/index.crates.io-6f17d22bba15001f/lazy_static-1.4.0/s
rc/lib.rs:142:21                                                                                                                                                                                                                              
    #10 0x564d059c99a7 in _$LT$iced_x86..formatter..fast..fmt_tbl..FMT_DATA$u20$as$u20$core..ops..deref..Deref$GT$::deref::h226c645a2243c5aa /home/vext01/.cargo/registry/src/index.crates.io-6f17d22bba15001f/lazy_static-1.4.0/src/lib.rs:14
4:17                                                                                                                                                                                                                                          
    #11 0x564d04ccd89e in iced_x86::formatter::fast::SpecializedFormatter$LT$TraitOptions$GT$::try_with_options::h4e5e9d568b60c51b /home/vext01/source/iced/src/rust/iced-x86/src/formatter/fast.rs:776:23                                    
    #12 0x564d04cc6e31 in iced_x86::formatter::fast::SpecializedFormatter$LT$TraitOptions$GT$::new::h3f80414dfbfcc847 /home/vext01/source/iced/src/rust/iced-x86/src/formatter/fast.rs:753:3                                                  
    #13 0x564d05d58149 in iced_x86::formatter::fast::tests::format_hex2::h7cc6a557a4ee1585 /home/vext01/source/iced/src/rust/iced-x86/src/formatter/fast/tests/mod.rs:128:27                                                                  
    #14 0x564d05bd0106 in iced_x86::formatter::fast::tests::format_hex2::_$u7b$$u7b$closure$u7d$$u7d$::h256851816dbd80ad /home/vext01/source/iced/src/rust/iced-x86/src/formatter/fast/tests/mod.rs:109:17                                    
    #15 0x564d0632ebea in test::types::RunnableTest::run::h36218d6a648d1201 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/test/src/types.rs:146:40                                            
    #16 0x564d062bfbf2 in test::run_test_in_process::_$u7b$$u7b$closure$u7d$$u7d$::hb227ced748144f42 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/test/src/lib.rs:643:60                     
    #17 0x564d06290b72 in _$LT$core..panic..unwind_safe..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::h68f075c3bc59fa64 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/l
ib/rustlib/src/rust/library/core/src/panic/unwind_safe.rs:272:9                                                                                                                                                                               
    #18 0x564d062402be in std::panicking::try::do_call::h09095b57b4461875 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:555:40                                           
    #19 0x564d06253f1a in __rust_try test.88cba25a81f58bb2-cgu.01                                                                                                                                                                             
    #20 0x564d0626f0cd in std::panic::catch_unwind::h8f677ee8bbe12892 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:142:14                                                   
    #21 0x564d062bdd34 in test::run_test::_$u7b$$u7b$closure$u7d$$u7d$::h770d75ef81e5dcab /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/test/src/lib.rs:566:43                                
    #22 0x564d062be4ef in test::run_test::_$u7b$$u7b$closure$u7d$$u7d$::h741ff39f58d00d99 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/test/src/lib.rs:594:41                                
    #23 0x564d0629233d in std::sys_common::backtrace::__rust_begin_short_backtrace::h999d2246d47b9dad /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/backtrace.rs:155:18    
    #24 0x564d0626f0ad in std::panic::catch_unwind::h5cf57153779a382a /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:142:14                                                   
    #25 0x564d0626fcbe in core::ops::function::FnOnce::call_once$u7b$$u7b$vtable.shim$u7d$$u7d$::h4988421d436d964a /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:
5                                                                                                                                                                                                                                             
    #26 0x564d06542c16 in _$LT$alloc..boxed..Box$LT$F$C$A$GT$$u20$as$u20$core..ops..function..FnOnce$LT$Args$GT$$GT$::call_once::h1a4bedae61e84932 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/libra
ry/alloc/src/boxed.rs:2016:9
    #27 0x564d0656ffb3 in std::sys::pal::unix::thread::Thread::new::thread_start::h9a0c56955487e0f2 /home/vext01/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/thread.rs:108:17
    #28 0x564d04b19ea8 in asan_thread_start(void*) /rustc/llvm/src/llvm-project/compiler-rt/lib/asan/asan_interceptors.cpp:239:28
...

They are likely to be real leaks, as the unstable book says:

It [asan] is not expected to produce false positive reports.

About this issue

Original URL
State: closed
Created 4 months ago
Comments: 16 (8 by maintainers)

Commits related to this issue

Keep a ref to vex map0 even if mvex feature is disabled Closes #524 — committed to icedland/iced by wtfsck 4 months ago
Keep a ref to vex map0 even if mvex feature is disabled Closes #524 — committed to icedland/iced by wtfsck 4 months ago

Most upvoted comments

Thanks!

On Sat, 24 Feb 2024, 17:55 wtfsck, @.***> wrote:

Closed #524 https://github.com/icedland/iced/issues/524 as completed via #528 https://github.com/icedland/iced/pull/528.

— Reply to this email directly, view it on GitHub https://github.com/icedland/iced/issues/524#event-11911277431, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAETWG3CR3QGZMENIYR4PTLYVISPTAVCNFSM6AAAAABDTCK4E6VHI2DSMVQWIX3LMV45UABCJFZXG5LFIV3GK3TUJZXXI2LGNFRWC5DJN5XDWMJRHEYTCMRXG42DGMI . You are receiving this because you authored the thread.Message ID: @.***>

vext01 on Feb 24, 2024

The problem isn’t related to pointer vs reference (asan doesn’t know anything about pointers vs references)

Manually expanding out the example that ASAN complains about:

let mut outer_vec: Vec<Thingy> = Vec::new();
let inner_vec: Vec<u8> = Vec::new(); // inner_vec is on the stack, its data is allocated on the heap
let tmp_boxed_vec: Box<Vec<u8>> = Box::new(inner_vec); // Now we box the vec itself (a data pointer, a length and a capacity), so there are two allocations, the box, and then the data inside the vec.
let tmp_vec_ref: &'static Vec<u8> = Box::leak(tmp_boxed_vec);
let leaked: *const u8 = tmp_vec_ref.as_ptr(); // We no longer have a pointer to the Vec which was boxed, only the vec's data
outer_vec.push(Thingy(leaked));
outer_vec

Instead, you can use Vec::leak directly, or Box::leak(vec.into_boxed_slice()) (to resize the allocation to exactly the right size rather than possibly keeping extra capacity).

Dr-Emann on Feb 23, 2024