ptrace/x86: ptrace_write_dr7() should create bp if !disabled
Commit 24f1e32c60
("hw-breakpoints: Rewrite the hw-breakpoints layer
on top of perf events") introduced the minor regression. Before this
commit
PTRACE_POKEUSER DR7, enableDR0
PTRACE_POKEUSER DR0, address
was perfectly valid, now PTRACE_POKEUSER(DR7) fails if DR0 was not
previously initialized by PTRACE_POKEUSER(DR0).
Change ptrace_write_dr7() to do ptrace_register_breakpoint(addr => 0) if
!bp && !disabled.
This fixes watchpoint-zeroaddr from ptrace-tests, see
https://bugzilla.redhat.com/show_bug.cgi?id=660204.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Jan Kratochvil <jan.kratochvil@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@kernel.org>
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>
This commit is contained in:
parent
9afe33ada2
commit
b87a95ad60
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@ -670,13 +670,16 @@ restore:
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if (!bp) {
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if (!bp) {
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if (disabled)
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if (disabled)
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continue;
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continue;
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/*
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* We should have at least an inactive breakpoint at
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bp = ptrace_register_breakpoint(tsk,
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* this slot. It means the user is writing dr7 without
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len, type, 0, disabled);
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* having written the address register first.
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if (IS_ERR(bp)) {
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*/
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rc = PTR_ERR(bp);
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rc = -EINVAL;
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break;
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break;
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}
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thread->ptrace_bps[i] = bp;
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continue;
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}
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}
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rc = ptrace_modify_breakpoint(bp, len, type, disabled);
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rc = ptrace_modify_breakpoint(bp, len, type, disabled);
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