On Fri Aug 18, 2023 at 9:07 PM EEST, Jack Wang wrote:
> We hit softlocup with following call trace:
>
> ? asm_sysvec_apic_timer_interrupt+0x16/0x20
> xa_erase+0x21/0xb0
> ? sgx_free_epc_page+0x20/0x50
> sgx_vepc_release+0x75/0x220
> __fput+0x89/0x250
> task_work_run+0x59/0x90
> do_exit+0x337/0x9a0
>
> Similar like commit 8795359e35bc ("x86/sgx: Silence softlockup detection
> when releasing large enclaves"). The test system has 64GB of enclave memory,
> and all assigned to a single VM. Release vepc take longer time and triggers
> the softlockup warning.
>
> Add cond_resched() to give other tasks a chance to run and placate
> the softlockup detector.
>
> Cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> Cc: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 540745ddbc70 ("x86/sgx: Introduce virtual EPC for use by KVM guests")
> Reported-by: Yu Zhang <yu.zhang@xxxxxxxxx>
> Tested-by: Yu Zhang <yu.zhang@xxxxxxxxx>
> Acked-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
> Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxx>
> ---
> v3:
> * improve commit message as suggested.
> * Add cond_resched() to the 3rd loop too.
> arch/x86/kernel/cpu/sgx/virt.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c
> index c3e37eaec8ec..7aaa3652e31d 100644
> --- a/arch/x86/kernel/cpu/sgx/virt.c
> +++ b/arch/x86/kernel/cpu/sgx/virt.c
> @@ -204,6 +204,7 @@ static int sgx_vepc_release(struct inode *inode, struct file *file)
> continue;
>
> xa_erase(&vepc->page_array, index);
> + cond_resched();
> }
>
> /*
> @@ -222,6 +223,7 @@ static int sgx_vepc_release(struct inode *inode, struct file *file)
> list_add_tail(&epc_page->list, &secs_pages);
>
> xa_erase(&vepc->page_array, index);
> + cond_resched();
> }
>
> /*
> @@ -243,6 +245,7 @@ static int sgx_vepc_release(struct inode *inode, struct file *file)
>
> if (sgx_vepc_free_page(epc_page))
> list_add_tail(&epc_page->list, &secs_pages);
> + cond_resched();
> }
>
> if (!list_empty(&secs_pages))
> --
> 2.34.1
Just acknowledging that my reviewed-by still holds for this patch.
BR, Jarkko
