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authorOleg Nesterov <oleg@redhat.com>2013-07-08 16:00:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-09 10:33:25 -0700
commit6961ed96f14463d7c6e38d8c2093f5d53bd70574 (patch)
tree210e317714fbee7abbe81f16f607693b00286364
parent02be46fba4b154b4a201a729b2d2b4ff6affd031 (diff)
ptrace/powerpc: revert "hw_breakpoints: Fix racy access to ptrace breakpoints"
This reverts commit 07fa7a0a8a58 ("hw_breakpoints: Fix racy access to ptrace breakpoints") and removes ptrace_get/put_breakpoints() added by other commits. The patch was fine but we can no longer race with SIGKILL after commit 9899d11f6544 ("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. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Michael Neuling <mikey@neuling.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> 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>
-rw-r--r--arch/powerpc/kernel/ptrace.c30
1 files changed, 4 insertions, 26 deletions
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 64f7bd5b1b0f..9a0d24c390a3 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -975,16 +975,12 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
hw_brk.type = (data & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
hw_brk.len = 8;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
- if (ptrace_get_breakpoints(task) < 0)
- return -ESRCH;
-
bp = thread->ptrace_bps[0];
if ((!data) || !(hw_brk.type & HW_BRK_TYPE_RDWR)) {
if (bp) {
unregister_hw_breakpoint(bp);
thread->ptrace_bps[0] = NULL;
}
- ptrace_put_breakpoints(task);
return 0;
}
if (bp) {
@@ -997,11 +993,9 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
ret = modify_user_hw_breakpoint(bp, &attr);
if (ret) {
- ptrace_put_breakpoints(task);
return ret;
}
thread->ptrace_bps[0] = bp;
- ptrace_put_breakpoints(task);
thread->hw_brk = hw_brk;
return 0;
}
@@ -1016,12 +1010,9 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
ptrace_triggered, NULL, task);
if (IS_ERR(bp)) {
thread->ptrace_bps[0] = NULL;
- ptrace_put_breakpoints(task);
return PTR_ERR(bp);
}
- ptrace_put_breakpoints(task);
-
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
task->thread.hw_brk = hw_brk;
#else /* CONFIG_PPC_ADV_DEBUG_REGS */
@@ -1440,26 +1431,19 @@ static long ppc_set_hwdebug(struct task_struct *child,
if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
brk.type |= HW_BRK_TYPE_WRITE;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
- if (ptrace_get_breakpoints(child) < 0)
- return -ESRCH;
-
/*
* Check if the request is for 'range' breakpoints. We can
* support it if range < 8 bytes.
*/
- if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE) {
+ if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE)
len = bp_info->addr2 - bp_info->addr;
- } else if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_EXACT)
+ else if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_EXACT)
len = 1;
- else {
- ptrace_put_breakpoints(child);
+ else
return -EINVAL;
- }
bp = thread->ptrace_bps[0];
- if (bp) {
- ptrace_put_breakpoints(child);
+ if (bp)
return -ENOSPC;
- }
/* Create a new breakpoint request if one doesn't exist already */
hw_breakpoint_init(&attr);
@@ -1471,11 +1455,9 @@ static long ppc_set_hwdebug(struct task_struct *child,
ptrace_triggered, NULL, child);
if (IS_ERR(bp)) {
thread->ptrace_bps[0] = NULL;
- ptrace_put_breakpoints(child);
return PTR_ERR(bp);
}
- ptrace_put_breakpoints(child);
return 1;
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
@@ -1519,16 +1501,12 @@ static long ppc_del_hwdebug(struct task_struct *child, long data)
return -EINVAL;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
- if (ptrace_get_breakpoints(child) < 0)
- return -ESRCH;
-
bp = thread->ptrace_bps[0];
if (bp) {
unregister_hw_breakpoint(bp);
thread->ptrace_bps[0] = NULL;
} else
ret = -ENOENT;
- ptrace_put_breakpoints(child);
return ret;
#else /* CONFIG_HAVE_HW_BREAKPOINT */
if (child->thread.hw_brk.address == 0)