Memory Leak [DO NOT CLOSE THIS] #8
Description
We need to continuously fix memory leaks. This issue is for reporting, tracking and fixing them, and also provides some guidance on detecting the root causes.
Guidance
We have set up some tracking capabilities in the memory allocator, including simple usage statistics, and more advanced allocation stack backtraces.
Memory usage statistics
This feature is always enabled. You can read /proc/meminfo2 to get the number of bytes currently allocated, such as:
starry:~# cat /proc/meminfo2
UsageStats { Rust Heap: 59252688, User Memory: 1638400, Page Cache: 524288, Page Table: 4317184, Dma: 24576, Global: 0 }Note: /proc/meminfo2 is a temporary path name and may be changed in the future.
Leak detect
This feature has some performance impact, so it needs to be enabled by specifying MEMTRACK=y while building. It can effectively record all newly allocated and unreclaimed memory over a period of time and record the applicants by generating a stack backtrace during allocation.
Usage:
$ make run MEMTRACK=y ...
...
starry:~# echo start > /dev/memtrack
Memory allocation generation stamped: 0
...
starry:~# echo end > /dev/memtrack
Alive tasks: ["Task(6, \"busybox\")", "Task(8, \"busybox\")"]
===========================
Memory usage:
72792 bytes, 3033 allocations, Layout { size: 24, align: 8 (1 << 3) }, Backtrace:
0: <axalloc::GlobalAllocator as core::alloc::global::GlobalAlloc>::alloc::{{closure}}
at /home/mizu/projects/os/StarryOS/arceos/modules/axalloc/src/lib.rs:416:40 with fp=0xffff000044c7f9c0, ip=0xffff0000403262e4
1: axalloc::tracking::with_state::{{closure}}
at /home/mizu/projects/os/StarryOS/arceos/modules/axalloc/src/lib.rs:360:30 with fp=0xffff000044c7f9c0, ip=0xffff0000403262e4
2: axalloc::tracking::IN_GLOBAL_ALLOCATOR_WRAPPER::with_current
at /home/mizu/projects/os/StarryOS/arceos/modules/axalloc/src/lib.rs:316:5 with fp=0xffff000044c7f9c0, ip=0xffff0000403262e4
3: axalloc::tracking::with_state
at /home/mizu/projects/os/StarryOS/arceos/modules/axalloc/src/lib.rs:354:9 with fp=0xffff000044c7f9c0, ip=0xffff0000403262e4
4: <axalloc::GlobalAllocator as core::alloc::global::GlobalAlloc>::alloc
at /home/mizu/projects/os/StarryOS/arceos/modules/axalloc/src/lib.rs:406:13 with fp=0xffff000044c7f9c0, ip=0xffff0000403262e4
5: alloc::alloc::alloc
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:93:9 with fp=0xffff000044c7fa20, ip=0xffff00004032b9a8
6: alloc::alloc::Global::alloc_impl
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:188:73 with fp=0xffff000044c7fa20, ip=0xffff00004032b9a8
7: <alloc::alloc::Global as core::alloc::Allocator>::allocate
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:249:9 with fp=0xffff000044c7fa20, ip=0xffff00004032b9a8
8: alloc::alloc::exchange_malloc
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:350:18 with fp=0xffff000044c7fa20, ip=0xffff00004032b9a8
9: alloc::boxed::Box<T>::new
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/boxed.rs:261:16 with fp=0xffff000044c7fa20, ip=0xffff00004032b9a8
10: axio::poll::PollSet::register
at /home/mizu/.cargo/git/checkouts/axio-00998c4fb7c77d99/e11ca75/src/poll.rs:67:45 with fp=0xffff000044c7fa20, ip=0xffff00004032b9a8
11: <starry_api::terminal::job::JobControl as axio::poll::Pollable>::register
at /home/mizu/projects/os/StarryOS/api/src/terminal/job.rs:79:13 with fp=0xffff000044c7fab0, ip=0xffff000040245f04
12: <starry_api::vfs::dev::tty::Tty<R,W> as axio::poll::Pollable>::register
at /home/mizu/projects/os/StarryOS/api/src/vfs/dev/tty.rs:199:13 with fp=0xffff000044c7fab0, ip=0xffff000040245f04
13: <starry_api::syscall::io_mpx::FdPollSet as axio::poll::Pollable>::register
at /home/mizu/projects/os/StarryOS/api/src/syscall/io_mpx/mod.rs:21:13 with fp=0xffff000044c7faf0, ip=0xffff00004024f5dc
14: axtask::future::Poller<P>::poll::{{closure}}
at /home/mizu/projects/os/StarryOS/arceos/modules/axtask/src/future.rs:267:25 with fp=0xffff000044c7faf0, ip=0xffff00004024f5dc
15: <core::future::poll_fn::PollFn<F> as core::future::future::Future>::poll
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/future/poll_fn.rs:151:9 with fp=0xffff000044c7faf0, ip=0xffff00004024f5dc
16: <axtask::future::Timeout<F> as core::future::future::Future>::poll
at /home/mizu/projects/os/StarryOS/arceos/modules/axtask/src/future.rs:214:13 with fp=0xffff000044c7fbf0, ip=0xffff000040213e68
17: <futures_util::future::future::map::Map<Fut,F> as core::future::future::Future>::poll
at /home/mizu/.cargo/registry/src/mirrors.cernet.edu.cn-cf4f1d0b4f95b1fb/futures-util-0.3.31/src/future/future/map.rs:55:37 with fp=0xffff000044c7fbf0, ip=0xffff000040213e68
18: <futures_util::future::future::Map<Fut,F> as core::future::future::Future>::poll
at /home/mizu/.cargo/registry/src/mirrors.cernet.edu.cn-cf4f1d0b4f95b1fb/futures-util-0.3.31/src/lib.rs:86:13 with fp=0xffff000044c7fbf0, ip=0xffff000040213e68
19: axtask::future::try_block_on
at /home/mizu/projects/os/StarryOS/arceos/modules/axtask/src/future.rs:83:15 with fp=0xffff000044c7fbf0, ip=0xffff000040213e68
20: axtask::future::block_on_interruptible
at /home/mizu/projects/os/StarryOS/arceos/modules/axtask/src/future.rs:111:5 with fp=0xffff000044c7fbf0, ip=0xffff000040213e68
21: axtask::future::Poller<P>::poll
at /home/mizu/projects/os/StarryOS/arceos/modules/axtask/src/future.rs:259:9 with fp=0xffff000044c7fbf0, ip=0xffff000040213e68
22: starry_api::syscall::io_mpx::poll::do_poll::{{closure}}
at /home/mizu/projects/os/StarryOS/api/src/syscall/io_mpx/poll.rs:56:15 with fp=0xffff000044c7fc70, ip=0xffff000040255a0c
23: starry_api::signal::with_replacen_blocked
at /home/mizu/projects/os/StarryOS/api/src/signal.rs:61:5 with fp=0xffff000044c7fc70, ip=0xffff000040255a0c
24: starry_api::syscall::io_mpx::poll::do_poll
at /home/mizu/projects/os/StarryOS/api/src/syscall/io_mpx/poll.rs:55:5 with fp=0xffff000044c7fd40, ip=0xffff00004026db24
25: starry_api::syscall::handle_syscall
at /home/mizu/projects/os/StarryOS/api/src/syscall/mod.rs:218:25 with fp=0xffff000044c7fdf0, ip=0xffff00004023096c
26: starry_api::task::new_user_task::{{closure}}
at /home/mizu/projects/os/StarryOS/api/src/task.rs:51:46 with fp=0xffff000044c7ff80, ip=0xffff00004023ee08
27: core::ops::function::FnOnce::call_once{{vtable.shim}}
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5 with fp=0xffff000044c7ff80, ip=0xffff00004023ee08
28: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/boxed.rs:1966:9 with fp=0xffff000044c7ffe0, ip=0xffff000040318760
29: axtask::task::task_entry
at /home/mizu/projects/os/StarryOS/arceos/modules/axtask/src/task.rs:559:9 with fp=0xffff000044c7ffe0, ip=0xffff000040318760
30: <alloc::sync::Arc<T,A> as core::clone::Clone>::clone
at /home/mizu/.rustup/toolchains/nightly-2025-05-20-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/sync.rs:2226:13 with fp=0x0, ip=0xffff000040318704
31: axtask::task::CurrentTask::clone
at /home/mizu/projects/os/StarryOS/arceos/modules/axtask/src/task.rs:510:24 with fp=0x0, ip=0xffff000040318704
25536 bytes, 12 allocations, Layout { size: 152, align: 8 (1 << 3) }, [lwext4]
4728 bytes, 24 allocations, Layout { size: 3616, align: 8 (1 << 3) }, [cached file]
2734 bytes, 21 allocations, Layout { size: 1224, align: 8 (1 << 3) }, [dentry]
...The output may be very long, so it is recommended to use it with tee.
Also note that /dev/memtrack may be changed in the future.