The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 8795359e35bc33bf86b6d0765aa7f37431db3b9c Gitweb: https://git.kernel.org/tip/8795359e35bc33bf86b6d0765aa7f37431db3b9c Author: Reinette Chatre reinette.chatre@intel.com AuthorDate: Tue, 08 Feb 2022 10:48:07 -08:00 Committer: Dave Hansen dave.hansen@linux.intel.com CommitterDate: Thu, 10 Feb 2022 15:58:14 -08:00
x86/sgx: Silence softlockup detection when releasing large enclaves
Vijay reported that the "unclobbered_vdso_oversubscribed" selftest triggers the softlockup detector.
Actual SGX systems have 128GB of enclave memory or more. The "unclobbered_vdso_oversubscribed" selftest creates one enclave which consumes all of the enclave memory on the system. Tearing down such a large enclave takes around a minute, most of it in the loop where the EREMOVE instruction is applied to each individual 4k enclave page.
Spending one minute in a loop triggers the softlockup detector.
Add a cond_resched() to give other tasks a chance to run and placate the softlockup detector.
Cc: stable@vger.kernel.org Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer") Reported-by: Vijay Dhanraj vijay.dhanraj@intel.com Signed-off-by: Reinette Chatre reinette.chatre@intel.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Jarkko Sakkinen jarkko@kernel.org Acked-by: Dave Hansen dave.hansen@linux.intel.com Tested-by: Jarkko Sakkinen jarkko@kernel.org (kselftest as sanity check) Link: https://lkml.kernel.org/r/ced01cac1e75f900251b0a4ae1150aa8ebd295ec.164434523... --- arch/x86/kernel/cpu/sgx/encl.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 001808e..48afe96 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -410,6 +410,8 @@ void sgx_encl_release(struct kref *ref) }
kfree(entry); + /* Invoke scheduler to prevent soft lockups. */ + cond_resched(); }
xa_destroy(&encl->page_array);