| Message ID | 20241209074125.52322-1-alexghiti@rivosinc.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | b3431a8bb336cece8adc452437befa7d4534b2fd |
| Headers | show |
| Series | [-fixes] riscv: Fix IPIs usage in kfence_protect_page() | expand |
Hello: This patch was applied to riscv/linux.git (fixes) by Palmer Dabbelt <palmer@rivosinc.com>: On Mon, 9 Dec 2024 08:41:25 +0100 you wrote: > flush_tlb_kernel_range() may use IPIs to flush the TLBs of all the > cores, which triggers the following warning when the irqs are disabled: > > [ 3.455330] WARNING: CPU: 1 PID: 0 at kernel/smp.c:815 smp_call_function_many_cond+0x452/0x520 > [ 3.456647] Modules linked in: > [ 3.457218] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.12.0-rc7-00010-g91d3de7240b8 #1 > [ 3.457416] Hardware name: QEMU QEMU Virtual Machine, BIOS > [ 3.457633] epc : smp_call_function_many_cond+0x452/0x520 > [ 3.457736] ra : on_each_cpu_cond_mask+0x1e/0x30 > [ 3.457786] epc : ffffffff800b669a ra : ffffffff800b67c2 sp : ff2000000000bb50 > [ 3.457824] gp : ffffffff815212b8 tp : ff6000008014f080 t0 : 000000000000003f > [ 3.457859] t1 : ffffffff815221e0 t2 : 000000000000000f s0 : ff2000000000bc10 > [ 3.457920] s1 : 0000000000000040 a0 : ffffffff815221e0 a1 : 0000000000000001 > [ 3.457953] a2 : 0000000000010000 a3 : 0000000000000003 a4 : 0000000000000000 > [ 3.458006] a5 : 0000000000000000 a6 : ffffffffffffffff a7 : 0000000000000000 > [ 3.458042] s2 : ffffffff815223be s3 : 00fffffffffff000 s4 : ff600001ffe38fc0 > [ 3.458076] s5 : ff600001ff950d00 s6 : 0000000200000120 s7 : 0000000000000001 > [ 3.458109] s8 : 0000000000000001 s9 : ff60000080841ef0 s10: 0000000000000001 > [ 3.458141] s11: ffffffff81524812 t3 : 0000000000000001 t4 : ff60000080092bc0 > [ 3.458172] t5 : 0000000000000000 t6 : ff200000000236d0 > [ 3.458203] status: 0000000200000100 badaddr: ffffffff800b669a cause: 0000000000000003 > [ 3.458373] [<ffffffff800b669a>] smp_call_function_many_cond+0x452/0x520 > [ 3.458593] [<ffffffff800b67c2>] on_each_cpu_cond_mask+0x1e/0x30 > [ 3.458625] [<ffffffff8000e4ca>] __flush_tlb_range+0x118/0x1ca > [ 3.458656] [<ffffffff8000e6b2>] flush_tlb_kernel_range+0x1e/0x26 > [ 3.458683] [<ffffffff801ea56a>] kfence_protect+0xc0/0xce > [ 3.458717] [<ffffffff801e9456>] kfence_guarded_free+0xc6/0x1c0 > [ 3.458742] [<ffffffff801e9d6c>] __kfence_free+0x62/0xc6 > [ 3.458764] [<ffffffff801c57d8>] kfree+0x106/0x32c > [ 3.458786] [<ffffffff80588cf2>] detach_buf_split+0x188/0x1a8 > [ 3.458816] [<ffffffff8058708c>] virtqueue_get_buf_ctx+0xb6/0x1f6 > [ 3.458839] [<ffffffff805871da>] virtqueue_get_buf+0xe/0x16 > [ 3.458880] [<ffffffff80613d6a>] virtblk_done+0x5c/0xe2 > [ 3.458908] [<ffffffff8058766e>] vring_interrupt+0x6a/0x74 > [ 3.458930] [<ffffffff800747d8>] __handle_irq_event_percpu+0x7c/0xe2 > [ 3.458956] [<ffffffff800748f0>] handle_irq_event+0x3c/0x86 > [ 3.458978] [<ffffffff800786cc>] handle_simple_irq+0x9e/0xbe > [ 3.459004] [<ffffffff80073934>] generic_handle_domain_irq+0x1c/0x2a > [ 3.459027] [<ffffffff804bf87c>] imsic_handle_irq+0xba/0x120 > [ 3.459056] [<ffffffff80073934>] generic_handle_domain_irq+0x1c/0x2a > [ 3.459080] [<ffffffff804bdb76>] riscv_intc_aia_irq+0x24/0x34 > [ 3.459103] [<ffffffff809d0452>] handle_riscv_irq+0x2e/0x4c > [ 3.459133] [<ffffffff809d923e>] call_on_irq_stack+0x32/0x40 > > [...] Here is the summary with links: - [-fixes] riscv: Fix IPIs usage in kfence_protect_page() https://git.kernel.org/riscv/c/b3431a8bb336 You are awesome, thank you!
Hi Alexandre, On Mon, Dec 9, 2024 at 4:46 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote: > > flush_tlb_kernel_range() may use IPIs to flush the TLBs of all the > cores, which triggers the following warning when the irqs are disabled: > > [ 3.455330] WARNING: CPU: 1 PID: 0 at kernel/smp.c:815 smp_call_function_many_cond+0x452/0x520 > [ 3.456647] Modules linked in: > [ 3.457218] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.12.0-rc7-00010-g91d3de7240b8 #1 > [ 3.457416] Hardware name: QEMU QEMU Virtual Machine, BIOS > [ 3.457633] epc : smp_call_function_many_cond+0x452/0x520 > [ 3.457736] ra : on_each_cpu_cond_mask+0x1e/0x30 > [ 3.457786] epc : ffffffff800b669a ra : ffffffff800b67c2 sp : ff2000000000bb50 > [ 3.457824] gp : ffffffff815212b8 tp : ff6000008014f080 t0 : 000000000000003f > [ 3.457859] t1 : ffffffff815221e0 t2 : 000000000000000f s0 : ff2000000000bc10 > [ 3.457920] s1 : 0000000000000040 a0 : ffffffff815221e0 a1 : 0000000000000001 > [ 3.457953] a2 : 0000000000010000 a3 : 0000000000000003 a4 : 0000000000000000 > [ 3.458006] a5 : 0000000000000000 a6 : ffffffffffffffff a7 : 0000000000000000 > [ 3.458042] s2 : ffffffff815223be s3 : 00fffffffffff000 s4 : ff600001ffe38fc0 > [ 3.458076] s5 : ff600001ff950d00 s6 : 0000000200000120 s7 : 0000000000000001 > [ 3.458109] s8 : 0000000000000001 s9 : ff60000080841ef0 s10: 0000000000000001 > [ 3.458141] s11: ffffffff81524812 t3 : 0000000000000001 t4 : ff60000080092bc0 > [ 3.458172] t5 : 0000000000000000 t6 : ff200000000236d0 > [ 3.458203] status: 0000000200000100 badaddr: ffffffff800b669a cause: 0000000000000003 > [ 3.458373] [<ffffffff800b669a>] smp_call_function_many_cond+0x452/0x520 > [ 3.458593] [<ffffffff800b67c2>] on_each_cpu_cond_mask+0x1e/0x30 > [ 3.458625] [<ffffffff8000e4ca>] __flush_tlb_range+0x118/0x1ca > [ 3.458656] [<ffffffff8000e6b2>] flush_tlb_kernel_range+0x1e/0x26 > [ 3.458683] [<ffffffff801ea56a>] kfence_protect+0xc0/0xce > [ 3.458717] [<ffffffff801e9456>] kfence_guarded_free+0xc6/0x1c0 > [ 3.458742] [<ffffffff801e9d6c>] __kfence_free+0x62/0xc6 > [ 3.458764] [<ffffffff801c57d8>] kfree+0x106/0x32c > [ 3.458786] [<ffffffff80588cf2>] detach_buf_split+0x188/0x1a8 > [ 3.458816] [<ffffffff8058708c>] virtqueue_get_buf_ctx+0xb6/0x1f6 > [ 3.458839] [<ffffffff805871da>] virtqueue_get_buf+0xe/0x16 > [ 3.458880] [<ffffffff80613d6a>] virtblk_done+0x5c/0xe2 > [ 3.458908] [<ffffffff8058766e>] vring_interrupt+0x6a/0x74 > [ 3.458930] [<ffffffff800747d8>] __handle_irq_event_percpu+0x7c/0xe2 > [ 3.458956] [<ffffffff800748f0>] handle_irq_event+0x3c/0x86 > [ 3.458978] [<ffffffff800786cc>] handle_simple_irq+0x9e/0xbe > [ 3.459004] [<ffffffff80073934>] generic_handle_domain_irq+0x1c/0x2a > [ 3.459027] [<ffffffff804bf87c>] imsic_handle_irq+0xba/0x120 > [ 3.459056] [<ffffffff80073934>] generic_handle_domain_irq+0x1c/0x2a > [ 3.459080] [<ffffffff804bdb76>] riscv_intc_aia_irq+0x24/0x34 > [ 3.459103] [<ffffffff809d0452>] handle_riscv_irq+0x2e/0x4c > [ 3.459133] [<ffffffff809d923e>] call_on_irq_stack+0x32/0x40 > > So only flush the local TLB and let the lazy kfence page fault handling > deal with the faults which could happen when a core has an old protected > pte version cached in its TLB. That leads to potential inaccuracies which > can be tolerated when using kfence. > > Fixes: 47513f243b45 ("riscv: Enable KFENCE for riscv64") > Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> > --- > arch/riscv/include/asm/kfence.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/include/asm/kfence.h b/arch/riscv/include/asm/kfence.h > index 7388edd88986..d08bf7fb3aee 100644 > --- a/arch/riscv/include/asm/kfence.h > +++ b/arch/riscv/include/asm/kfence.h > @@ -22,7 +22,9 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect) > else > set_pte(pte, __pte(pte_val(ptep_get(pte)) | _PAGE_PRESENT)); > > - flush_tlb_kernel_range(addr, addr + PAGE_SIZE); > + preempt_disable(); > + local_flush_tlb_kernel_range(addr, addr + PAGE_SIZE); > + preempt_enable(); > > return true; > } > -- > 2.39.2 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv Reviewed-by: Yong-Xuan Wang <yongxuan.wang@sifive.com> Regards, Yong-Xuan
diff --git a/arch/riscv/include/asm/kfence.h b/arch/riscv/include/asm/kfence.h index 7388edd88986..d08bf7fb3aee 100644 --- a/arch/riscv/include/asm/kfence.h +++ b/arch/riscv/include/asm/kfence.h @@ -22,7 +22,9 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect) else set_pte(pte, __pte(pte_val(ptep_get(pte)) | _PAGE_PRESENT)); - flush_tlb_kernel_range(addr, addr + PAGE_SIZE); + preempt_disable(); + local_flush_tlb_kernel_range(addr, addr + PAGE_SIZE); + preempt_enable(); return true; }
flush_tlb_kernel_range() may use IPIs to flush the TLBs of all the cores, which triggers the following warning when the irqs are disabled: [ 3.455330] WARNING: CPU: 1 PID: 0 at kernel/smp.c:815 smp_call_function_many_cond+0x452/0x520 [ 3.456647] Modules linked in: [ 3.457218] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.12.0-rc7-00010-g91d3de7240b8 #1 [ 3.457416] Hardware name: QEMU QEMU Virtual Machine, BIOS [ 3.457633] epc : smp_call_function_many_cond+0x452/0x520 [ 3.457736] ra : on_each_cpu_cond_mask+0x1e/0x30 [ 3.457786] epc : ffffffff800b669a ra : ffffffff800b67c2 sp : ff2000000000bb50 [ 3.457824] gp : ffffffff815212b8 tp : ff6000008014f080 t0 : 000000000000003f [ 3.457859] t1 : ffffffff815221e0 t2 : 000000000000000f s0 : ff2000000000bc10 [ 3.457920] s1 : 0000000000000040 a0 : ffffffff815221e0 a1 : 0000000000000001 [ 3.457953] a2 : 0000000000010000 a3 : 0000000000000003 a4 : 0000000000000000 [ 3.458006] a5 : 0000000000000000 a6 : ffffffffffffffff a7 : 0000000000000000 [ 3.458042] s2 : ffffffff815223be s3 : 00fffffffffff000 s4 : ff600001ffe38fc0 [ 3.458076] s5 : ff600001ff950d00 s6 : 0000000200000120 s7 : 0000000000000001 [ 3.458109] s8 : 0000000000000001 s9 : ff60000080841ef0 s10: 0000000000000001 [ 3.458141] s11: ffffffff81524812 t3 : 0000000000000001 t4 : ff60000080092bc0 [ 3.458172] t5 : 0000000000000000 t6 : ff200000000236d0 [ 3.458203] status: 0000000200000100 badaddr: ffffffff800b669a cause: 0000000000000003 [ 3.458373] [<ffffffff800b669a>] smp_call_function_many_cond+0x452/0x520 [ 3.458593] [<ffffffff800b67c2>] on_each_cpu_cond_mask+0x1e/0x30 [ 3.458625] [<ffffffff8000e4ca>] __flush_tlb_range+0x118/0x1ca [ 3.458656] [<ffffffff8000e6b2>] flush_tlb_kernel_range+0x1e/0x26 [ 3.458683] [<ffffffff801ea56a>] kfence_protect+0xc0/0xce [ 3.458717] [<ffffffff801e9456>] kfence_guarded_free+0xc6/0x1c0 [ 3.458742] [<ffffffff801e9d6c>] __kfence_free+0x62/0xc6 [ 3.458764] [<ffffffff801c57d8>] kfree+0x106/0x32c [ 3.458786] [<ffffffff80588cf2>] detach_buf_split+0x188/0x1a8 [ 3.458816] [<ffffffff8058708c>] virtqueue_get_buf_ctx+0xb6/0x1f6 [ 3.458839] [<ffffffff805871da>] virtqueue_get_buf+0xe/0x16 [ 3.458880] [<ffffffff80613d6a>] virtblk_done+0x5c/0xe2 [ 3.458908] [<ffffffff8058766e>] vring_interrupt+0x6a/0x74 [ 3.458930] [<ffffffff800747d8>] __handle_irq_event_percpu+0x7c/0xe2 [ 3.458956] [<ffffffff800748f0>] handle_irq_event+0x3c/0x86 [ 3.458978] [<ffffffff800786cc>] handle_simple_irq+0x9e/0xbe [ 3.459004] [<ffffffff80073934>] generic_handle_domain_irq+0x1c/0x2a [ 3.459027] [<ffffffff804bf87c>] imsic_handle_irq+0xba/0x120 [ 3.459056] [<ffffffff80073934>] generic_handle_domain_irq+0x1c/0x2a [ 3.459080] [<ffffffff804bdb76>] riscv_intc_aia_irq+0x24/0x34 [ 3.459103] [<ffffffff809d0452>] handle_riscv_irq+0x2e/0x4c [ 3.459133] [<ffffffff809d923e>] call_on_irq_stack+0x32/0x40 So only flush the local TLB and let the lazy kfence page fault handling deal with the faults which could happen when a core has an old protected pte version cached in its TLB. That leads to potential inaccuracies which can be tolerated when using kfence. Fixes: 47513f243b45 ("riscv: Enable KFENCE for riscv64") Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> --- arch/riscv/include/asm/kfence.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)