starred/qemu
1
0
Fork 0
mirror of https://github.com/qemu/qemu.git synced 2026-04-05 22:00:58 +00:00
Code Issues 380 Packages Projects Releases Wiki Activity

linux-user: update select timeout writeback

Browse Source 
The Linux kernel writes back the remaining timeout for select-family
syscalls in poll_select_finish(). If that writeback fails, it keeps
the original return value.

However, QEMU only writes back the timeout on success. If the writeback
fails, QEMU returns -TARGET_EFAULT. This can lose the remaining
timeout and change the return value.

Update do_select(), do_pselect6(), and do_ppoll() to always write back
the timeout to match the Linux kernel's behavior. If the timeout
writeback fails, keep the original return value.

Tested with the issue reproducer.

Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3343
Signed-off-by: Sun Haoyu <shyliuli@aosc.io>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20260320111647.138984-1-shyliuli@aosc.io
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Sun Haoyu
2026-03-20 19:16:47 +08:00
committed by Peter Maydell
parent 22966937f4
commit 9b7d64686b
1 changed files with 24 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

45
linux-user/syscall.c
View File

@@ -1384,14 +1384,15 @@ static abi_long do_select(int n,
return -TARGET_EFAULT;
if (efd_addr && copy_to_user_fdset(efd_addr, &efds, n))
return -TARGET_EFAULT;
if (target_tv_addr) {
tv.tv_sec = ts.tv_sec;
tv.tv_usec = ts.tv_nsec / 1000;
if (copy_to_user_timeval(target_tv_addr, &tv)) {
return -TARGET_EFAULT;
}
}
}
if (target_tv_addr) {
tv.tv_sec = ts.tv_sec;
tv.tv_usec = ts.tv_nsec / 1000;
/*
* Like the kernel, we deliberately ignore possible
* failures writing back to the timeout struct.
*/
copy_to_user_timeval(target_tv_addr, &tv);
}
return ret;
@@ -1519,14 +1520,16 @@ static abi_long do_pselect6(abi_long arg1, abi_long arg2, abi_long arg3,
if (efd_addr && copy_to_user_fdset(efd_addr, &efds, n)) {
return -TARGET_EFAULT;
}
}
if (ts_addr) {
/*
* Like the kernel, we deliberately ignore possible
* failures writing back to the timeout struct.
*/
if (time64) {
if (ts_addr && host_to_target_timespec64(ts_addr, &ts)) {
return -TARGET_EFAULT;
}
host_to_target_timespec64(ts_addr, &ts);
} else {
if (ts_addr && host_to_target_timespec(ts_addr, &ts)) {
return -TARGET_EFAULT;
}
host_to_target_timespec(ts_addr, &ts);
}
}
return ret;
@@ -1596,15 +1599,15 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2, abi_long arg3,
if (set) {
finish_sigsuspend_mask(ret);
}
if (!is_error(ret) && arg3) {
if (arg3) {
/*
* Like the kernel, we deliberately ignore possible
* failures writing back to the timeout struct.
*/
if (time64) {
if (host_to_target_timespec64(arg3, timeout_ts)) {
return -TARGET_EFAULT;
}
host_to_target_timespec64(arg3, timeout_ts);
} else {
if (host_to_target_timespec(arg3, timeout_ts)) {
return -TARGET_EFAULT;
}
host_to_target_timespec(arg3, timeout_ts);
}
}
} else {