From 7f2a53c231fe5d9522c3b695ab454203904031ac Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 17 Aug 2020 10:37:22 -0700 Subject: rcu: Remove unused __rcu_is_watching() function The x86/entry work removed all uses of __rcu_is_watching(), therefore this commit removes it entirely. Cc: Andy Lutomirski Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Signed-off-by: Paul E. McKenney --- kernel/entry/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/entry/common.c') diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 9852e0d62d95..ad794a10fa80 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -278,7 +278,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs) * terminate a grace period, if and only if the timer interrupt is * not nested into another interrupt. * - * Checking for __rcu_is_watching() here would prevent the nesting + * Checking for rcu_is_watching() here would prevent the nesting * interrupt to invoke rcu_irq_enter(). If that nested interrupt is * the tick then rcu_flavor_sched_clock_irq() would wrongfully * assume that it is the first interupt and eventually claim -- cgit v1.2.3 From 3c532798ec96b6c2d77706f04ed1d8b566a805df Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 3 Oct 2020 10:49:22 -0600 Subject: tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume() All the callers currently do this, clean it up and move the clearing into tracehook_notify_resume() instead. Reviewed-by: Oleg Nesterov Reviewed-by: Thomas Gleixner Signed-off-by: Jens Axboe --- arch/alpha/kernel/signal.c | 1 - arch/arc/kernel/signal.c | 2 +- arch/arm/kernel/signal.c | 1 - arch/arm64/kernel/signal.c | 1 - arch/c6x/kernel/signal.c | 4 +--- arch/csky/kernel/signal.c | 1 - arch/h8300/kernel/signal.c | 4 +--- arch/hexagon/kernel/process.c | 1 - arch/ia64/kernel/process.c | 2 +- arch/m68k/kernel/signal.c | 2 +- arch/microblaze/kernel/signal.c | 2 +- arch/mips/kernel/signal.c | 1 - arch/nds32/kernel/signal.c | 4 +--- arch/nios2/kernel/signal.c | 2 +- arch/openrisc/kernel/signal.c | 1 - arch/parisc/kernel/signal.c | 4 +--- arch/powerpc/kernel/signal.c | 1 - arch/riscv/kernel/signal.c | 4 +--- arch/s390/kernel/signal.c | 1 - arch/sh/kernel/signal_32.c | 4 +--- arch/sparc/kernel/signal_32.c | 4 +--- arch/sparc/kernel/signal_64.c | 4 +--- arch/um/kernel/process.c | 2 +- arch/xtensa/kernel/signal.c | 2 +- include/linux/tracehook.h | 4 ++-- kernel/entry/common.c | 1 - kernel/entry/kvm.c | 4 +--- 27 files changed, 18 insertions(+), 46 deletions(-) (limited to 'kernel/entry/common.c') diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c index 15bc9d1e79f4..3739efce1ec0 100644 --- a/arch/alpha/kernel/signal.c +++ b/arch/alpha/kernel/signal.c @@ -531,7 +531,6 @@ do_work_pending(struct pt_regs *regs, unsigned long thread_flags, do_signal(regs, r0, r19); r0 = 0; } else { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); } } diff --git a/arch/arc/kernel/signal.c b/arch/arc/kernel/signal.c index 8222f8c54690..2be55fb96d87 100644 --- a/arch/arc/kernel/signal.c +++ b/arch/arc/kernel/signal.c @@ -394,6 +394,6 @@ void do_notify_resume(struct pt_regs *regs) * ASM glue gaurantees that this is only called when returning to * user mode */ - if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) + if (test_thread_flag(TIF_NOTIFY_RESUME)) tracehook_notify_resume(regs); } diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index c1892f733f20..585edbfccf6d 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -669,7 +669,6 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) } else if (thread_flags & _TIF_UPROBE) { uprobe_notify_resume(regs); } else { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); } diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index bdcaaf091e1e..a8184cad8890 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -946,7 +946,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, do_signal(regs); if (thread_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); } diff --git a/arch/c6x/kernel/signal.c b/arch/c6x/kernel/signal.c index d05c78eace1b..a3f15b9a79da 100644 --- a/arch/c6x/kernel/signal.c +++ b/arch/c6x/kernel/signal.c @@ -316,8 +316,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags, if (thread_info_flags & (1 << TIF_SIGPENDING)) do_signal(regs, syscall); - if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) tracehook_notify_resume(regs); - } } diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c index 970895df75ec..8b068cf37447 100644 --- a/arch/csky/kernel/signal.c +++ b/arch/csky/kernel/signal.c @@ -261,7 +261,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, do_signal(regs); if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); } diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c index 69e68949787f..75d9b7e626b2 100644 --- a/arch/h8300/kernel/signal.c +++ b/arch/h8300/kernel/signal.c @@ -282,8 +282,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags) if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); - if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (thread_info_flags & _TIF_NOTIFY_RESUME) tracehook_notify_resume(regs); - } } diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c index dfd322c5ce83..5a0a95d93ddb 100644 --- a/arch/hexagon/kernel/process.c +++ b/arch/hexagon/kernel/process.c @@ -180,7 +180,6 @@ int do_work_pending(struct pt_regs *regs, u32 thread_info_flags) } if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); return 1; } diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index f25f2f723196..6b61a703bcf5 100644 --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -176,7 +176,7 @@ do_notify_resume_user(sigset_t *unused, struct sigscratch *scr, long in_syscall) ia64_do_signal(scr, in_syscall); } - if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) { + if (test_thread_flag(TIF_NOTIFY_RESUME)) { local_irq_enable(); /* force interrupt enable */ tracehook_notify_resume(&scr->pt); } diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c index a98fca977073..29e174a80bf6 100644 --- a/arch/m68k/kernel/signal.c +++ b/arch/m68k/kernel/signal.c @@ -1134,6 +1134,6 @@ void do_notify_resume(struct pt_regs *regs) if (test_thread_flag(TIF_SIGPENDING)) do_signal(regs); - if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) + if (test_thread_flag(TIF_NOTIFY_RESUME)) tracehook_notify_resume(regs); } diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c index 4a96b59f0bee..f11a0ccccabc 100644 --- a/arch/microblaze/kernel/signal.c +++ b/arch/microblaze/kernel/signal.c @@ -316,6 +316,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall) if (test_thread_flag(TIF_SIGPENDING)) do_signal(regs, in_syscall); - if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) + if (test_thread_flag(TIF_NOTIFY_RESUME)) tracehook_notify_resume(regs); } diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c index f44265025281..50d0515bea21 100644 --- a/arch/mips/kernel/signal.c +++ b/arch/mips/kernel/signal.c @@ -907,7 +907,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused, do_signal(regs); if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); } diff --git a/arch/nds32/kernel/signal.c b/arch/nds32/kernel/signal.c index 36e25a410bb0..2acb94812af9 100644 --- a/arch/nds32/kernel/signal.c +++ b/arch/nds32/kernel/signal.c @@ -379,8 +379,6 @@ do_notify_resume(struct pt_regs *regs, unsigned int thread_flags) if (thread_flags & _TIF_SIGPENDING) do_signal(regs); - if (thread_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (thread_flags & _TIF_NOTIFY_RESUME) tracehook_notify_resume(regs); - } } diff --git a/arch/nios2/kernel/signal.c b/arch/nios2/kernel/signal.c index d8a087cf2b42..cf2dca2ac7c3 100644 --- a/arch/nios2/kernel/signal.c +++ b/arch/nios2/kernel/signal.c @@ -317,7 +317,7 @@ asmlinkage int do_notify_resume(struct pt_regs *regs) */ return restart; } - } else if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) + } else if (test_thread_flag(TIF_NOTIFY_RESUME)) tracehook_notify_resume(regs); return 0; diff --git a/arch/openrisc/kernel/signal.c b/arch/openrisc/kernel/signal.c index c779364f0cd0..af66f968dd45 100644 --- a/arch/openrisc/kernel/signal.c +++ b/arch/openrisc/kernel/signal.c @@ -311,7 +311,6 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) } syscall = 0; } else { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); } } diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c index 3c037fc96038..9f43eaeb0b0a 100644 --- a/arch/parisc/kernel/signal.c +++ b/arch/parisc/kernel/signal.c @@ -606,8 +606,6 @@ void do_notify_resume(struct pt_regs *regs, long in_syscall) if (test_thread_flag(TIF_SIGPENDING)) do_signal(regs, in_syscall); - if (test_thread_flag(TIF_NOTIFY_RESUME)) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (test_thread_flag(TIF_NOTIFY_RESUME)) tracehook_notify_resume(regs); - } } diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c index d15a98c758b8..74a94a125f0d 100644 --- a/arch/powerpc/kernel/signal.c +++ b/arch/powerpc/kernel/signal.c @@ -327,7 +327,6 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) } if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); } diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index e996e08f1061..bc6841867b51 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -313,8 +313,6 @@ asmlinkage __visible void do_notify_resume(struct pt_regs *regs, if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); - if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (thread_info_flags & _TIF_NOTIFY_RESUME) tracehook_notify_resume(regs); - } } diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c index b295090e2ce6..9e900a8977bd 100644 --- a/arch/s390/kernel/signal.c +++ b/arch/s390/kernel/signal.c @@ -535,7 +535,6 @@ void do_signal(struct pt_regs *regs) void do_notify_resume(struct pt_regs *regs) { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); } diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c index 4fe3f00137bc..1add47fd31f6 100644 --- a/arch/sh/kernel/signal_32.c +++ b/arch/sh/kernel/signal_32.c @@ -502,8 +502,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs, save_r0); - if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (thread_info_flags & _TIF_NOTIFY_RESUME) tracehook_notify_resume(regs); - } } diff --git a/arch/sparc/kernel/signal_32.c b/arch/sparc/kernel/signal_32.c index d0e0025ee3ba..741d0701003a 100644 --- a/arch/sparc/kernel/signal_32.c +++ b/arch/sparc/kernel/signal_32.c @@ -523,10 +523,8 @@ void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, { if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs, orig_i0); - if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (thread_info_flags & _TIF_NOTIFY_RESUME) tracehook_notify_resume(regs); - } } asmlinkage int do_sys_sigstack(struct sigstack __user *ssptr, diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c index 255264bcb46a..f7ef7edcd5c1 100644 --- a/arch/sparc/kernel/signal_64.c +++ b/arch/sparc/kernel/signal_64.c @@ -551,10 +551,8 @@ void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long uprobe_notify_resume(regs); if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs, orig_i0); - if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (thread_info_flags & _TIF_NOTIFY_RESUME) tracehook_notify_resume(regs); - } user_enter(); } diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c index 26b5e243d3fc..3bed09538dd9 100644 --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -101,7 +101,7 @@ void interrupt_end(void) schedule(); if (test_thread_flag(TIF_SIGPENDING)) do_signal(regs); - if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) + if (test_thread_flag(TIF_NOTIFY_RESUME)) tracehook_notify_resume(regs); } diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c index b3b17d6c50f0..1fb1047f905c 100644 --- a/arch/xtensa/kernel/signal.c +++ b/arch/xtensa/kernel/signal.c @@ -501,6 +501,6 @@ void do_notify_resume(struct pt_regs *regs) if (test_thread_flag(TIF_SIGPENDING)) do_signal(regs); - if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) + if (test_thread_flag(TIF_NOTIFY_RESUME)) tracehook_notify_resume(regs); } diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 36fb3bbed6b2..b480e1a07ed8 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -178,9 +178,9 @@ static inline void set_notify_resume(struct task_struct *task) */ static inline void tracehook_notify_resume(struct pt_regs *regs) { + clear_thread_flag(TIF_NOTIFY_RESUME); /* - * The caller just cleared TIF_NOTIFY_RESUME. This barrier - * pairs with task_work_add()->set_notify_resume() after + * This barrier pairs with task_work_add()->set_notify_resume() after * hlist_add_head(task->task_works); */ smp_mb__after_atomic(); diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 145ab11b8318..971ef788b9ae 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -161,7 +161,6 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, arch_do_signal(regs); if (ti_work & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); } diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c index eb1a8a4c867c..b6678a5e3cf6 100644 --- a/kernel/entry/kvm.c +++ b/kernel/entry/kvm.c @@ -16,10 +16,8 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) if (ti_work & _TIF_NEED_RESCHED) schedule(); - if (ti_work & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); + if (ti_work & _TIF_NOTIFY_RESUME) tracehook_notify_resume(NULL); - } ret = arch_xfer_to_guest_mode_handle_work(vcpu, ti_work); if (ret) -- cgit v1.2.3 From 9d820f68b2bdba5b2e7bf135123c3f57c5051d05 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 4 Nov 2020 14:06:23 +0100 Subject: entry: Fix the incorrect ordering of lockdep and RCU check When an exception/interrupt hits kernel space and the kernel is not currently in the idle task then RCU must be watching. irqentry_enter() validates this via rcu_irq_enter_check_tick(), which in turn invokes lockdep when taking a lock. But at that point lockdep does not yet know about the fact that interrupts have been disabled by the CPU, which triggers a lockdep splat complaining about inconsistent state. Invoking trace_hardirqs_off() before rcu_irq_enter_check_tick() defeats the point of rcu_irq_enter_check_tick() because trace_hardirqs_off() uses RCU. So use the same sequence as for the idle case and tell lockdep about the irq state change first, invoke the RCU check and then do the lockdep and tracer update. Fixes: a5497bab5f72 ("entry: Provide generic interrupt entry/exit code") Reported-by: Mark Rutland Signed-off-by: Thomas Gleixner Tested-by: Mark Rutland Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/87y2jhl19s.fsf@nanos.tec.linutronix.de --- kernel/entry/common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/entry/common.c') diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 2b8366693d5c..e9e2df3f3f9e 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -337,10 +337,10 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs) * already contains a warning when RCU is not watching, so no point * in having another one here. */ + lockdep_hardirqs_off(CALLER_ADDR0); instrumentation_begin(); rcu_irq_enter_check_tick(); - /* Use the combo lockdep/tracing function */ - trace_hardirqs_off(); + trace_hardirqs_off_finish(); instrumentation_end(); return ret; -- cgit v1.2.3