From: guoren@kernel.org To: arnd@arndb.de, guoren@kernel.org, palmer@rivosinc.com, tglx@linutronix.de, peterz@infradead.org, luto@kernel.org, conor.dooley@microchip.com, heiko@sntech.de, jszhang@kernel.org, lazyparser@gmail.com, falcon@tinylab.org, chenhuacai@kernel.org, apatel@ventanamicro.com, atishp@atishpatra.org, palmer@dabbelt.com, paul.walmsley@sifive.com, mark.rutland@arm.com, zouyipeng@huawei.com, bigeasy@linutronix.de, David.Laight@aculab.com Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Guo Ren <guoren@linux.alibaba.com> Subject: [PATCH V5 06/11] entry: Prevent DEBUG_PREEMPT warning Date: Sun, 18 Sep 2022 11:52:41 -0400 [thread overview] Message-ID: <20220918155246.1203293-7-guoren@kernel.org> (raw) In-Reply-To: <20220918155246.1203293-1-guoren@kernel.org> From: Guo Ren <guoren@linux.alibaba.com> When DEBUG_PREEMPT=y, exit_to_user_mode_prepare ->tick_nohz_user_enter_prepare ->tick_nohz_full_cpu(smp_processor_id()) ->smp_processor_id() ->debug_smp_processor_id() ->check preempt_count() then: [ 5.717610] BUG: using smp_processor_id() in preemptible [00000000] code: S20urandom/94 [ 5.718111] caller is debug_smp_processor_id+0x24/0x38 [ 5.718417] CPU: 1 PID: 94 Comm: S20urandom Not tainted 6.0.0-rc3-00010-gfd0a0d619c63-dirty #238 [ 5.718886] Hardware name: riscv-virtio,qemu (DT) [ 5.719136] Call Trace: [ 5.719281] [<ffffffff800055fc>] dump_backtrace+0x2c/0x3c [ 5.719566] [<ffffffff80ae6cb0>] show_stack+0x44/0x5c [ 5.720023] [<ffffffff80aee870>] dump_stack_lvl+0x74/0xa4 [ 5.720557] [<ffffffff80aee8bc>] dump_stack+0x1c/0x2c [ 5.721033] [<ffffffff80af65c0>] check_preemption_disabled+0x104/0x108 [ 5.721538] [<ffffffff80af65e8>] debug_smp_processor_id+0x24/0x38 [ 5.722001] [<ffffffff800aee30>] exit_to_user_mode_prepare+0x48/0x178 [ 5.722355] [<ffffffff80af5bf4>] irqentry_exit_to_user_mode+0x18/0x30 [ 5.722685] [<ffffffff80af5c70>] irqentry_exit+0x64/0xa4 [ 5.722953] [<ffffffff80af52f4>] do_page_fault+0x1d8/0x544 [ 5.723291] [<ffffffff80003310>] ret_from_exception+0x0/0xb8 (Above is found in riscv platform with generic_entry) The smp_processor_id() needs irqs disable or preempt_disable, so use preempt dis/in protecting the tick_nohz_user_enter_prepare(). Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> --- kernel/entry/common.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 063068a9ea9b..36e4cd50531c 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -194,8 +194,10 @@ static void exit_to_user_mode_prepare(struct pt_regs *regs) lockdep_assert_irqs_disabled(); + preempt_disable(); /* Flush pending rcuog wakeup before the last need_resched() check */ tick_nohz_user_enter_prepare(); + preempt_enable(); if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK)) ti_work = exit_to_user_mode_loop(regs, ti_work); -- 2.36.1
WARNING: multiple messages have this Message-ID (diff)
From: guoren@kernel.org To: arnd@arndb.de, guoren@kernel.org, palmer@rivosinc.com, tglx@linutronix.de, peterz@infradead.org, luto@kernel.org, conor.dooley@microchip.com, heiko@sntech.de, jszhang@kernel.org, lazyparser@gmail.com, falcon@tinylab.org, chenhuacai@kernel.org, apatel@ventanamicro.com, atishp@atishpatra.org, palmer@dabbelt.com, paul.walmsley@sifive.com, mark.rutland@arm.com, zouyipeng@huawei.com, bigeasy@linutronix.de, David.Laight@aculab.com Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Guo Ren <guoren@linux.alibaba.com> Subject: [PATCH V5 06/11] entry: Prevent DEBUG_PREEMPT warning Date: Sun, 18 Sep 2022 11:52:41 -0400 [thread overview] Message-ID: <20220918155246.1203293-7-guoren@kernel.org> (raw) In-Reply-To: <20220918155246.1203293-1-guoren@kernel.org> From: Guo Ren <guoren@linux.alibaba.com> When DEBUG_PREEMPT=y, exit_to_user_mode_prepare ->tick_nohz_user_enter_prepare ->tick_nohz_full_cpu(smp_processor_id()) ->smp_processor_id() ->debug_smp_processor_id() ->check preempt_count() then: [ 5.717610] BUG: using smp_processor_id() in preemptible [00000000] code: S20urandom/94 [ 5.718111] caller is debug_smp_processor_id+0x24/0x38 [ 5.718417] CPU: 1 PID: 94 Comm: S20urandom Not tainted 6.0.0-rc3-00010-gfd0a0d619c63-dirty #238 [ 5.718886] Hardware name: riscv-virtio,qemu (DT) [ 5.719136] Call Trace: [ 5.719281] [<ffffffff800055fc>] dump_backtrace+0x2c/0x3c [ 5.719566] [<ffffffff80ae6cb0>] show_stack+0x44/0x5c [ 5.720023] [<ffffffff80aee870>] dump_stack_lvl+0x74/0xa4 [ 5.720557] [<ffffffff80aee8bc>] dump_stack+0x1c/0x2c [ 5.721033] [<ffffffff80af65c0>] check_preemption_disabled+0x104/0x108 [ 5.721538] [<ffffffff80af65e8>] debug_smp_processor_id+0x24/0x38 [ 5.722001] [<ffffffff800aee30>] exit_to_user_mode_prepare+0x48/0x178 [ 5.722355] [<ffffffff80af5bf4>] irqentry_exit_to_user_mode+0x18/0x30 [ 5.722685] [<ffffffff80af5c70>] irqentry_exit+0x64/0xa4 [ 5.722953] [<ffffffff80af52f4>] do_page_fault+0x1d8/0x544 [ 5.723291] [<ffffffff80003310>] ret_from_exception+0x0/0xb8 (Above is found in riscv platform with generic_entry) The smp_processor_id() needs irqs disable or preempt_disable, so use preempt dis/in protecting the tick_nohz_user_enter_prepare(). Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> --- kernel/entry/common.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 063068a9ea9b..36e4cd50531c 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -194,8 +194,10 @@ static void exit_to_user_mode_prepare(struct pt_regs *regs) lockdep_assert_irqs_disabled(); + preempt_disable(); /* Flush pending rcuog wakeup before the last need_resched() check */ tick_nohz_user_enter_prepare(); + preempt_enable(); if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK)) ti_work = exit_to_user_mode_loop(regs, ti_work); -- 2.36.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2022-09-18 15:54 UTC|newest] Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-09-18 15:52 [PATCH V5 00/11] riscv: Add GENERIC_ENTRY support and related features guoren 2022-09-18 15:52 ` guoren 2022-09-18 15:52 ` [PATCH V5 01/11] riscv: elf_kexec: Fixup compile warning guoren 2022-09-18 15:52 ` guoren 2022-09-18 15:52 ` [PATCH V5 02/11] riscv: compat_syscall_table: " guoren 2022-09-18 15:52 ` guoren 2022-09-18 15:52 ` [PATCH V5 03/11] riscv: ptrace: Remove duplicate operation guoren 2022-09-18 15:52 ` guoren 2022-09-18 15:52 ` [PATCH V5 04/11] compiler_types.h: Add __noinstr_section() for noinstr guoren 2022-09-18 15:52 ` guoren 2022-09-18 15:52 ` [PATCH V5 05/11] riscv: traps: Add noinstr to prevent instrumentation inserted guoren 2022-09-18 15:52 ` guoren 2022-09-18 15:52 ` guoren [this message] 2022-09-18 15:52 ` [PATCH V5 06/11] entry: Prevent DEBUG_PREEMPT warning guoren 2022-09-19 11:58 ` Peter Zijlstra 2022-09-19 11:58 ` Peter Zijlstra 2022-09-20 1:45 ` Guo Ren 2022-09-20 1:45 ` Guo Ren 2022-09-30 12:27 ` Guo Ren 2022-09-30 12:27 ` Guo Ren 2022-09-18 15:52 ` [PATCH V5 07/11] riscv: convert to generic entry guoren 2022-09-18 15:52 ` guoren 2022-09-19 13:34 ` Peter Zijlstra 2022-09-19 13:34 ` Peter Zijlstra 2022-09-20 6:36 ` Guo Ren 2022-09-20 6:36 ` Guo Ren 2022-09-20 7:22 ` Peter Zijlstra 2022-09-20 7:22 ` Peter Zijlstra 2022-09-30 11:28 ` Guo Ren 2022-09-30 11:28 ` Guo Ren 2022-09-18 15:52 ` [PATCH V5 08/11] riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK guoren 2022-09-18 15:52 ` guoren 2022-09-19 13:45 ` Peter Zijlstra 2022-09-19 13:45 ` Peter Zijlstra 2022-09-20 6:08 ` Guo Ren 2022-09-20 6:08 ` Guo Ren 2022-09-20 7:27 ` Peter Zijlstra 2022-09-20 7:27 ` Peter Zijlstra 2022-09-20 7:34 ` Peter Zijlstra 2022-09-20 7:34 ` Peter Zijlstra 2022-09-21 6:16 ` Guo Ren 2022-09-21 6:16 ` Guo Ren 2022-09-21 8:34 ` Chen Zhongjin 2022-09-21 8:34 ` Chen Zhongjin 2022-09-21 9:53 ` Guo Ren 2022-09-21 9:53 ` Guo Ren 2022-09-21 11:56 ` Chen Zhongjin 2022-09-21 11:56 ` Chen Zhongjin 2022-09-22 1:26 ` Guo Ren 2022-09-22 1:26 ` Guo Ren 2022-09-18 15:52 ` [PATCH V5 09/11] riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK guoren 2022-09-18 15:52 ` guoren 2022-09-20 0:11 ` Guo Ren 2022-09-20 0:11 ` Guo Ren 2022-09-18 15:52 ` [PATCH V5 10/11] riscv: Add config of thread stack size guoren 2022-09-18 15:52 ` guoren 2022-09-18 15:52 ` [PATCH V5 11/11] riscv: Add support for STACKLEAK gcc plugin guoren 2022-09-18 15:52 ` guoren
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