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linux-user: do setrlimit selectively 

setrlimit guest calls that affect memory resources
(RLIMIT_{AS,DATA,STACK}) may interfere with QEMU internal memory
management. They may result in QEMU lockup because mprotect call in
page_unprotect would fail with ENOMEM error code, causing infinite loop
of SIGSEGV. E.g. it happens when running libstdc++ testsuite for xtensa
target on x86_64 host.

Don't call host setrlimit for memory-related resources.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Message-Id: <20180917181314.22551-1-jcmvbkbc@gmail.com>
[lv: rebase on master]
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Max Filippov 2018-09-17 11:13:14 -07:00 committed by Laurent Vivier
parent 58cfa6c2e6
commit 5dfa88f716
1 changed files with 15 additions and 1 deletions
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16
linux-user/syscall.c
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@ -7879,7 +7879,21 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
rlim.rlim_cur = target_to_host_rlim(target_rlim->rlim_cur);
rlim.rlim_max = target_to_host_rlim(target_rlim->rlim_max);
unlock_user_struct(target_rlim, arg2, 0);
return get_errno(setrlimit(resource, &rlim));
/*
* If we just passed through resource limit settings for memory then
* they would also apply to QEMU's own allocations, and QEMU will
* crash or hang or die if its allocations fail. Ideally we would
* track the guest allocations in QEMU and apply the limits ourselves.
* For now, just tell the guest the call succeeded but don't actually
* limit anything.
*/
if (resource != RLIMIT_AS &&
resource != RLIMIT_DATA &&
resource != RLIMIT_STACK) {
return get_errno(setrlimit(resource, &rlim));
} else {
return 0;
}
}
#endif
#ifdef TARGET_NR_getrlimit