ptrace/x86: revert "hw_breakpoints: Fix racy access to ptrace breakpoints" (02be46fb) · Commits · 戴 / test

This reverts commit ("hw_breakpoints: Fix racy access to ptrace breakpoints"). The patch was fine but we can no longer race with SIGKILL after commit ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL"), the __TASK_TRACED tracee can't be woken up and ->ptrace_bps[] can't go away. The patch only removes ptrace_get_breakpoints/ptrace_put_breakpoints and does a couple of "while at it" cleanups, it doesn't remove other changes from the reverted commit. Signed-off-by:

Oleg Nesterov <oleg@redhat.com> Acked-by:

Ingo Molnar <mingo@kernel.org> Acked-by:

Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/ptrace.c

+5 −23

Original line number	Diff line number	Diff line
		@@ -641,9 +641,6 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
		unsigned len, type;
		struct perf_event *bp;

		if (ptrace_get_breakpoints(tsk) < 0)
		return -ESRCH;

		data &= ~DR_CONTROL_RESERVED;
		old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
		restore:
		@@ -692,9 +689,7 @@ restore:
		goto restore;
		}

		ptrace_put_breakpoints(tsk);

		return ((orig_ret < 0) ? orig_ret : rc);
		return orig_ret < 0 ? orig_ret : rc;
		}

		/*
		@@ -706,18 +701,10 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
		unsigned long val = 0;

		if (n < HBP_NUM) {
		struct perf_event *bp;
		struct perf_event *bp = thread->ptrace_bps[n];

		if (ptrace_get_breakpoints(tsk) < 0)
		return -ESRCH;

		bp = thread->ptrace_bps[n];
		if (!bp)
		val = 0;
		else
		if (bp)
		val = bp->hw.info.address;

		ptrace_put_breakpoints(tsk);
		} else if (n == 6) {
		val = thread->debugreg6;
		} else if (n == 7) {
		@@ -734,9 +721,6 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
		struct perf_event_attr attr;
		int err = 0;

		if (ptrace_get_breakpoints(tsk) < 0)
		return -ESRCH;

		if (!t->ptrace_bps[nr]) {
		ptrace_breakpoint_init(&attr);
		/*
		@@ -762,7 +746,7 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
		*/
		if (IS_ERR(bp)) {
		err = PTR_ERR(bp);
		goto put;
		goto out;
		}

		t->ptrace_bps[nr] = bp;
		@@ -773,9 +757,7 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
		attr.bp_addr = addr;
		err = modify_user_hw_breakpoint(bp, &attr);
		}

		put:
		ptrace_put_breakpoints(tsk);
		out:
		return err;
		}

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