| Message ID | b5e9f218064aa76e3026f778e1ad0a1d823e3db8.1643133224.git.reinette.chatre@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [V2] x86/sgx: Silence softlockup detection when releasing large enclaves | expand |
On Tue, Jan 25, 2022 at 10:22:43AM -0800, Reinette Chatre wrote: > 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> > Acked-by: Dave Hansen <dave.hansen@linux.intel.com> > Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> > --- > Softlockup message: > > watchdog: BUG: soft lockup - CPU#7 stuck for 22s! [test_sgx:11502] > Kernel panic - not syncing: softlockup: hung tasks > <snip> > sgx_encl_release+0x86/0x1c0 > sgx_release+0x11c/0x130 > __fput+0xb0/0x280 > ____fput+0xe/0x10 > task_work_run+0x6c/0xc0 > exit_to_user_mode_prepare+0x1eb/0x1f0 > syscall_exit_to_user_mode+0x1d/0x50 > do_syscall_64+0x46/0xb0 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > Changes since V1: > - V1: https://lore.kernel.org/lkml/1aa037705e5aa209d8b7a075873c6b4190327436.1642530802.git.reinette.chatre@intel.com/ > - Add comment provided by Jarkko. > > 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 001808e3901c..48afe96ae0f0 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); > -- > 2.25.1 > Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Tested-by: Jarkko Sakkinen <jarkko@kernel.org> (kselftest as sanity check) BR, Jarkko
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 001808e3901c..48afe96ae0f0 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);
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> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> --- Softlockup message: watchdog: BUG: soft lockup - CPU#7 stuck for 22s! [test_sgx:11502] Kernel panic - not syncing: softlockup: hung tasks <snip> sgx_encl_release+0x86/0x1c0 sgx_release+0x11c/0x130 __fput+0xb0/0x280 ____fput+0xe/0x10 task_work_run+0x6c/0xc0 exit_to_user_mode_prepare+0x1eb/0x1f0 syscall_exit_to_user_mode+0x1d/0x50 do_syscall_64+0x46/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae Changes since V1: - V1: https://lore.kernel.org/lkml/1aa037705e5aa209d8b7a075873c6b4190327436.1642530802.git.reinette.chatre@intel.com/ - Add comment provided by Jarkko. arch/x86/kernel/cpu/sgx/encl.c | 2 ++ 1 file changed, 2 insertions(+)