| Message ID | 20180917181314.22551-1-jcmvbkbc@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] linux-user: do setrlimit selectively | expand |
Le 17/09/2018 à 20:13, Max Filippov a écrit : > 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> > --- > Changes v2->v3: > - add comment sugessted by Peter > > Changes v1->v2: > - don't limit change to 32-bit guest on 64-bit host case > > linux-user/syscall.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) rebased on master and applied on my branch linux-user-for-3.1 Thanks, Laurent
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index bb42a225eb58..f06307ebd945 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -9275,7 +9275,21 @@ abi_long do_syscall(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); - ret = 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; + } } break; #endif
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> --- Changes v2->v3: - add comment sugessted by Peter Changes v1->v2: - don't limit change to 32-bit guest on 64-bit host case linux-user/syscall.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)