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Avoid deadlocks with app execution aliases - #373
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dscho merged 1 commit intoSep 28, 2026
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Calling `winget.exe` through its app execution alias from an interactive MSYS2 shell can leave the shell hanging after `winget.exe` exits. This affects all app execution aliases, not only `winget.exe`. App execution alias handling was introduced in 0631c66 (Cygwin: Treat Windows Store's "app execution aliases" as symbolic links, 2021-03-22), and 6c3d269 (Cygwin: termios: Handle app execution alias in is_console_app(), 2025-12-10) taught `is_console_app()` to follow aliases using another `path_conv`, which allocates cygheap memory. 618eb90fc2 (Cygwin: console: Fix undesired mode change at exit of non-cygwin apps, 2026-09-19) added a second `is_console_app()` call from `wait_for_resume_if_necessary()`. Unfortunately, at that point, `child_info_spawn::worker()` already holds the non-recursive `cygheap_protect`, so following an alias tries to acquire the same lock recursively and deadlocks. Let's avoid running `is_console_app()` under that lock by instead classifying the executable _once_, in `spawn_worker::setup()`, before acquiring the cygheap lock, then cache and reuse the result for both PTY setup and the post-resume wait. Addresses: msys2#372 Fixes: 618eb90fc2 (Cygwin: console: Fix undesired mode change at exit of non-cygwin apps, 2026-09-19) Signed-off-by: Christoph Reiter <reiter.christoph@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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lazka
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Sep 28, 2026
msys2/msys2-runtime#372 reports that calling `winget.exe` through its app execution alias from an interactive MSYS2 shell can leave the shell hanging after `winget.exe` exits. This affects all app execution aliases, not only `winget.exe`. App execution alias handling was introduced in 0631c66 (Cygwin: Treat Windows Store's "app execution aliases" as symbolic links, 2021-03-22), and 6c3d269 (Cygwin: termios: Handle app execution alias in is_console_app(), 2025-12-10) taught `is_console_app()` to follow aliases using another `path_conv`, which allocates cygheap memory. 618eb90fc2 (Cygwin: console: Fix undesired mode change at exit of non-cygwin apps, 2026-09-19) added a second `is_console_app()` call from `wait_for_resume_if_necessary()`. Unfortunately, at that point, `child_info_spawn::worker()` already holds the non-recursive `cygheap_protect`, so following an alias tries to acquire the same lock recursively and deadlocks. Let's avoid running `is_console_app()` under that lock by instead classifying the executable _once_, in `spawn_worker::setup()`, before acquiring the cygheap lock, then cache and reuse the result for both PTY setup and the post-resume wait. This addresses msys2/msys2-runtime#372 This corresponds to msys2/msys2-runtime#373
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Sep 28, 2026
…736) msys2/msys2-runtime#372 reports that calling `winget.exe` through its app execution alias from an interactive MSYS2 shell can leave the shell hanging after `winget.exe` exits. This affects all app execution aliases, not only `winget.exe`. App execution alias handling was introduced in 0631c6644e (Cygwin: Treat Windows Store's "app execution aliases" as symbolic links, 2021-03-22), and 6c3d26961d (Cygwin: termios: Handle app execution alias in is_console_app(), 2025-12-10) taught `is_console_app()` to follow aliases using another `path_conv`, which allocates cygheap memory. 618eb90fc2 (Cygwin: console: Fix undesired mode change at exit of non-cygwin apps, 2026-09-19) added a second `is_console_app()` call from `wait_for_resume_if_necessary()`. Unfortunately, at that point, `child_info_spawn::worker()` already holds the non-recursive `cygheap_protect`, so following an alias tries to acquire the same lock recursively and deadlocks. Let's avoid running `is_console_app()` under that lock by instead classifying the executable _once_, in `spawn_worker::setup()`, before acquiring the cygheap lock, then cache and reuse the result for both PTY setup and the post-resume wait. This addresses msys2/msys2-runtime#372 This corresponds to msys2/msys2-runtime#373 Source: msys2/MSYS2-packages@3c4cc77
catull
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Oct 8, 2026
msys2/msys2-runtime#372 reports that calling `winget.exe` through its app execution alias from an interactive MSYS2 shell can leave the shell hanging after `winget.exe` exits. This affects all app execution aliases, not only `winget.exe`. App execution alias handling was introduced in 0631c66 (Cygwin: Treat Windows Store's "app execution aliases" as symbolic links, 2021-03-22), and 6c3d269 (Cygwin: termios: Handle app execution alias in is_console_app(), 2025-12-10) taught `is_console_app()` to follow aliases using another `path_conv`, which allocates cygheap memory. 618eb90fc2 (Cygwin: console: Fix undesired mode change at exit of non-cygwin apps, 2026-09-19) added a second `is_console_app()` call from `wait_for_resume_if_necessary()`. Unfortunately, at that point, `child_info_spawn::worker()` already holds the non-recursive `cygheap_protect`, so following an alias tries to acquire the same lock recursively and deadlocks. Let's avoid running `is_console_app()` under that lock by instead classifying the executable _once_, in `spawn_worker::setup()`, before acquiring the cygheap lock, then cache and reuse the result for both PTY setup and the post-resume wait. This addresses msys2/msys2-runtime#372 This corresponds to msys2/msys2-runtime#373
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#372 reports that calling
winget.exethrough its app execution alias from an interactive MSYS2 shell can leave the shell hanging afterwinget.exeexits. This affects all app execution aliases, not onlywinget.exe.App execution alias handling was introduced in 0631c66 (Cygwin: Treat Windows Store's "app execution aliases" as symbolic links, 2021-03-22), and 6c3d269 (Cygwin: termios: Handle app execution alias in is_console_app(), 2025-12-10) taught
is_console_app()to follow aliases using anotherpath_conv, which allocates cygheap memory.618eb90fc2 (Cygwin: console: Fix undesired mode change at exit of non-cygwin apps, 2026-09-19) added a second
is_console_app()call fromwait_for_resume_if_necessary(). Unfortunately, at that point,child_info_spawn::worker()already holds the non-recursivecygheap_protect, so following an alias tries to acquire the same lock recursively and deadlocks.Let's avoid running
is_console_app()under that lock by instead classifying the executable once, inspawn_worker::setup(), before acquiring the cygheap lock, then cache and reuse the result for both PTY setup and the post-resume wait.This addresses #372