From bdd06f82a186a509256d1b3c2dd9282f4c96553f Mon Sep 17 00:00:00 2001 From: Christian Franke Date: Wed, 23 Oct 2024 11:44:34 +0200 Subject: [PATCH] cygwin: pread/pwrite: prevent EBADF error after fork() If the parent process has already used pread() or pwrite(), these functions fail with EBADF if used on the inherited fd. Ensure that fix_after_fork() is called to invalidate the prw_handle. This issue has been detected by 'stress-ng --pseek 1'. Fixes: c36cd56c548a ("* fhandler.cc (fhandler_base::open): Drop local create_options variable.") Signed-off-by: Christian Franke --- winsup/cygwin/fhandler/disk_file.cc | 3 +++ winsup/cygwin/release/3.5.5 | 3 +++ 2 files changed, 6 insertions(+) diff --git a/winsup/cygwin/fhandler/disk_file.cc b/winsup/cygwin/fhandler/disk_file.cc index f4c21d3b7..2008fb61b 100644 --- a/winsup/cygwin/fhandler/disk_file.cc +++ b/winsup/cygwin/fhandler/disk_file.cc @@ -1803,6 +1803,9 @@ fhandler_disk_file::prw_open (bool write, void *aio) return -1; } + /* prw_handle is invalid after fork. */ + need_fork_fixup (true); + /* record prw_handle's asyncness for subsequent pread/pwrite operations */ prw_handle_isasync = !!aio; return 0; diff --git a/winsup/cygwin/release/3.5.5 b/winsup/cygwin/release/3.5.5 index 904119a38..d01f31c60 100644 --- a/winsup/cygwin/release/3.5.5 +++ b/winsup/cygwin/release/3.5.5 @@ -7,3 +7,6 @@ Fixes: - Fix a regression in 3.5.4 that writing to pipe extremely slows down. Addresses: https://cygwin.com/pipermail/cygwin/2024-August/256398.html + +- Fix pread() and pwrite() EBADF error after fork(). + Addresses: https://sourceware.org/pipermail/cygwin/2024-September/256468.html