Messages in this thread | | | Subject | Re: [PATCH] x86/sgx: Silence softlockup detection when releasing large enclaves | From | Jarkko Sakkinen <> | Date | Thu, 20 Jan 2022 15:01:29 +0200 |
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On Tue, 2022-01-18 at 11:14 -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 > > arch/x86/kernel/cpu/sgx/encl.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c > b/arch/x86/kernel/cpu/sgx/encl.c > index 001808e3901c..ab2b79327a8a 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -410,6 +410,7 @@ void sgx_encl_release(struct kref *ref) > } > > kfree(entry); > + cond_resched(); > } > > xa_destroy(&encl->page_array);
I'd add a comment, e.g.
/* Invoke scheduler to prevent soft lockups. */
Other than that makes sense.
BR, Jarkko
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