Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull force_sig() argument change from Eric Biederman:
 "A source of error over the years has been that force_sig has taken a
  task parameter when it is only safe to use force_sig with the current
  task.

  The force_sig function is built for delivering synchronous signals
  such as SIGSEGV where the userspace application caused a synchronous
  fault (such as a page fault) and the kernel responded with a signal.

  Because the name force_sig does not make this clear, and because the
  force_sig takes a task parameter the function force_sig has been
  abused for sending other kinds of signals over the years. Slowly those
  have been fixed when the oopses have been tracked down.

  This set of changes fixes the remaining abusers of force_sig and
  carefully rips out the task parameter from force_sig and friends
  making this kind of error almost impossible in the future"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
  signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus
  signal: Remove the signal number and task parameters from force_sig_info
  signal: Factor force_sig_info_to_task out of force_sig_info
  signal: Generate the siginfo in force_sig
  signal: Move the computation of force into send_signal and correct it.
  signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal
  signal: Remove the task parameter from force_sig_fault
  signal: Use force_sig_fault_to_task for the two calls that don't deliver to current
  signal: Explicitly call force_sig_fault on current
  signal/unicore32: Remove tsk parameter from __do_user_fault
  signal/arm: Remove tsk parameter from __do_user_fault
  signal/arm: Remove tsk parameter from ptrace_break
  signal/nds32: Remove tsk parameter from send_sigtrap
  signal/riscv: Remove tsk parameter from do_trap
  signal/sh: Remove tsk parameter from force_sig_info_fault
  signal/um: Remove task parameter from send_sigtrap
  signal/x86: Remove task parameter from send_sigtrap
  signal: Remove task parameter from force_sig_mceerr
  signal: Remove task parameter from force_sig
  signal: Remove task parameter from force_sigsegv
  ...

12 files changed, 23 insertions, 30 deletions

diff --git a/arch/sh/kernel/cpu/sh2a/fpu.c b/arch/sh/kernel/cpu/sh2a/fpu.c
index 74b48db86dd7..0bcff11a4843 100644
--- a/arch/sh/kernel/cpu/sh2a/fpu.c
+++ b/arch/sh/kernel/cpu/sh2a/fpu.c
@@ -568,5 +568,5 @@ BUILD_TRAP_HANDLER(fpu_error)
 		return;
 	}
 
-	force_sig(SIGFPE, tsk);
+	force_sig(SIGFPE);
 }
diff --git a/arch/sh/kernel/cpu/sh4/fpu.c b/arch/sh/kernel/cpu/sh4/fpu.c
index 1ff56e5ba990..03ffd8cdf542 100644
--- a/arch/sh/kernel/cpu/sh4/fpu.c
+++ b/arch/sh/kernel/cpu/sh4/fpu.c
@@ -421,5 +421,5 @@ BUILD_TRAP_HANDLER(fpu_error)
 		}
 	}
 
-	force_sig(SIGFPE, tsk);
+	force_sig(SIGFPE);
 }
diff --git a/arch/sh/kernel/cpu/sh5/fpu.c b/arch/sh/kernel/cpu/sh5/fpu.c
index 9218d9ed787e..3966b5ee8e93 100644
--- a/arch/sh/kernel/cpu/sh5/fpu.c
+++ b/arch/sh/kernel/cpu/sh5/fpu.c
@@ -100,9 +100,7 @@ void restore_fpu(struct task_struct *tsk)
 
 asmlinkage void do_fpu_error(unsigned long ex, struct pt_regs *regs)
 {
-	struct task_struct *tsk = current;
-
 	regs->pc += 4;
 
-	force_sig(SIGFPE, tsk);
+	force_sig(SIGFPE);
 }
diff --git a/arch/sh/kernel/hw_breakpoint.c b/arch/sh/kernel/hw_breakpoint.c
index bc96b16288c1..3bd010b4c55f 100644
--- a/arch/sh/kernel/hw_breakpoint.c
+++ b/arch/sh/kernel/hw_breakpoint.c
@@ -338,7 +338,7 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args)
 		/* Deliver the signal to userspace */
 		if (!arch_check_bp_in_kernelspace(&bp->hw.info)) {
 			force_sig_fault(SIGTRAP, TRAP_HWBKPT,
-					(void __user *)NULL, current);
+					(void __user *)NULL);
 		}
 
 		rcu_read_unlock();
diff --git a/arch/sh/kernel/ptrace_64.c b/arch/sh/kernel/ptrace_64.c
index 3390349ff976..11085e48eaa6 100644
--- a/arch/sh/kernel/ptrace_64.c
+++ b/arch/sh/kernel/ptrace_64.c
@@ -550,7 +550,7 @@ asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
 	   continually stepping. */
 	local_irq_enable();
 	regs->sr &= ~SR_SSTEP;
-	force_sig(SIGTRAP, current);
+	force_sig(SIGTRAP);
 }
 
 /* Called with interrupts disabled */
@@ -561,7 +561,7 @@ BUILD_TRAP_HANDLER(breakpoint)
 	/* We need to forward step the PC, to counteract the backstep done
 	   in signal.c. */
 	local_irq_enable();
-	force_sig(SIGTRAP, current);
+	force_sig(SIGTRAP);
 	regs->pc += 4;
 }
 
diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
index 2a2121ba8ebe..24473fa6c3b6 100644
--- a/arch/sh/kernel/signal_32.c
+++ b/arch/sh/kernel/signal_32.c
@@ -176,7 +176,7 @@ asmlinkage int sys_sigreturn(void)
 	return r0;
 
 badframe:
-	force_sig(SIGSEGV, current);
+	force_sig(SIGSEGV);
 	return 0;
 }
 
@@ -207,7 +207,7 @@ asmlinkage int sys_rt_sigreturn(void)
 	return r0;
 
 badframe:
-	force_sig(SIGSEGV, current);
+	force_sig(SIGSEGV);
 	return 0;
 }
 
diff --git a/arch/sh/kernel/signal_64.c b/arch/sh/kernel/signal_64.c
index f1f1598879c2..b9aaa9266b34 100644
--- a/arch/sh/kernel/signal_64.c
+++ b/arch/sh/kernel/signal_64.c
@@ -277,7 +277,7 @@ asmlinkage int sys_sigreturn(unsigned long r2, unsigned long r3,
 	return (int) ret;
 
 badframe:
-	force_sig(SIGSEGV, current);
+	force_sig(SIGSEGV);
 	return 0;
 }
 
@@ -311,7 +311,7 @@ asmlinkage int sys_rt_sigreturn(unsigned long r2, unsigned long r3,
 	return (int) ret;
 
 badframe:
-	force_sig(SIGSEGV, current);
+	force_sig(SIGSEGV);
 	return 0;
 }
 
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index 8b49cced663d..63cf17bc760d 100644
--- a/arch/sh/kernel/traps.c
+++ b/arch/sh/kernel/traps.c
@@ -141,7 +141,7 @@ BUILD_TRAP_HANDLER(debug)
 		       SIGTRAP) == NOTIFY_STOP)
 		return;
 
-	force_sig(SIGTRAP, current);
+	force_sig(SIGTRAP);
 }
 
 /*
@@ -167,7 +167,7 @@ BUILD_TRAP_HANDLER(bug)
 	}
 #endif
 
-	force_sig(SIGTRAP, current);
+	force_sig(SIGTRAP);
 }
 
 BUILD_TRAP_HANDLER(nmi)
diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index f2a18b5fafd8..058c6181bb30 100644
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -533,7 +533,7 @@ uspace_segv:
 		       "access (PC %lx PR %lx)\n", current->comm, regs->pc,
 		       regs->pr);
 
-		force_sig_fault(SIGBUS, si_code, (void __user *)address, current);
+		force_sig_fault(SIGBUS, si_code, (void __user *)address);
 	} else {
 		inc_unaligned_kernel_access();
 
@@ -603,7 +603,7 @@ asmlinkage void do_divide_error(unsigned long r4)
 		/* Let gcc know unhandled cases don't make it past here */
 		return;
 	}
-	force_sig_fault(SIGFPE, code, NULL, current);
+	force_sig_fault(SIGFPE, code, NULL);
 }
 #endif
 
@@ -611,7 +611,6 @@ asmlinkage void do_reserved_inst(void)
 {
 	struct pt_regs *regs = current_pt_regs();
 	unsigned long error_code;
-	struct task_struct *tsk = current;
 
 #ifdef CONFIG_SH_FPU_EMU
 	unsigned short inst = 0;
@@ -633,7 +632,7 @@ asmlinkage void do_reserved_inst(void)
 		/* Enable DSP mode, and restart instruction. */
 		regs->sr |= SR_DSP;
 		/* Save DSP mode */
-		tsk->thread.dsp_status.status |= SR_DSP;
+		current->thread.dsp_status.status |= SR_DSP;
 		return;
 	}
 #endif
@@ -641,7 +640,7 @@ asmlinkage void do_reserved_inst(void)
 	error_code = lookup_exception_vector();
 
 	local_irq_enable();
-	force_sig(SIGILL, tsk);
+	force_sig(SIGILL);
 	die_if_no_fixup("reserved instruction", regs, error_code);
 }
 
@@ -697,7 +696,6 @@ asmlinkage void do_illegal_slot_inst(void)
 {
 	struct pt_regs *regs = current_pt_regs();
 	unsigned long inst;
-	struct task_struct *tsk = current;
 
 	if (kprobe_handle_illslot(regs->pc) == 0)
 		return;
@@ -716,7 +714,7 @@ asmlinkage void do_illegal_slot_inst(void)
 	inst = lookup_exception_vector();
 
 	local_irq_enable();
-	force_sig(SIGILL, tsk);
+	force_sig(SIGILL);
 	die_if_no_fixup("illegal slot instruction", regs, inst);
 }
 
diff --git a/arch/sh/kernel/traps_64.c b/arch/sh/kernel/traps_64.c
index 8ce90a7da67d..37046f3a26d3 100644
--- a/arch/sh/kernel/traps_64.c
+++ b/arch/sh/kernel/traps_64.c
@@ -599,7 +599,7 @@ static void do_unhandled_exception(int signr, char *str, unsigned long error,
 				   struct pt_regs *regs)
 {
 	if (user_mode(regs))
-		force_sig(signr, current);
+		force_sig(signr);
 
 	die_if_no_fixup(str, regs, error);
 }
diff --git a/arch/sh/math-emu/math.c b/arch/sh/math-emu/math.c
index a0fa8fc88739..e8be0eca0444 100644
--- a/arch/sh/math-emu/math.c
+++ b/arch/sh/math-emu/math.c
@@ -560,7 +560,7 @@ static int ieee_fpe_handler(struct pt_regs *regs)
 			task_thread_info(tsk)->status |= TS_USEDFPU;
 		} else {
 			force_sig_fault(SIGFPE, FPE_FLTINV,
-					(void __user *)regs->pc, tsk);
+					(void __user *)regs->pc);
 		}
 
 		regs->pc = nextpc;
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index 6defd2c6d9b1..3093bc372138 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -39,10 +39,9 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap)
 }
 
 static void
-force_sig_info_fault(int si_signo, int si_code, unsigned long address,
-		     struct task_struct *tsk)
+force_sig_info_fault(int si_signo, int si_code, unsigned long address)
 {
-	force_sig_fault(si_signo, si_code, (void __user *)address, tsk);
+	force_sig_fault(si_signo, si_code, (void __user *)address);
 }
 
 /*
@@ -244,8 +243,6 @@ static void
 __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		       unsigned long address, int si_code)
 {
-	struct task_struct *tsk = current;
-
 	/* User mode accesses just cause a SIGSEGV */
 	if (user_mode(regs)) {
 		/*
@@ -253,7 +250,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		 */
 		local_irq_enable();
 
-		force_sig_info_fault(SIGSEGV, si_code, address, tsk);
+		force_sig_info_fault(SIGSEGV, si_code, address);
 
 		return;
 	}
@@ -308,7 +305,7 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
 	if (!user_mode(regs))
 		no_context(regs, error_code, address);
 
-	force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
+	force_sig_info_fault(SIGBUS, BUS_ADRERR, address);
 }
 
 static noinline int