Subject: [merged] ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch removed from -mm tree
To: oleg@xxxxxxxxxx,benh@xxxxxxxxxxxxxxxxxxx,fweisbec@xxxxxxxxx,jan.kratochvil@xxxxxxxxxx,lethal@xxxxxxxxxxxx,linux@xxxxxxxxxxxxxxxx,mikey@xxxxxxxxxxx,mingo@xxxxxxxxxx,paulus@xxxxxxxxx,prasad@xxxxxxxxxxxxxxxxxx,will.deacon@xxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 09 Jul 2013 16:21:03 -0700
The patch titled
Subject: ptrace/x86: revert "hw_breakpoints: Fix racy access to ptrace breakpoints"
has been removed from the -mm tree. Its filename was
ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: ptrace/x86: revert "hw_breakpoints: Fix racy access to ptrace breakpoints"
This reverts commit 87dc669ba257 ("hw_breakpoints: Fix racy access to
ptrace breakpoints").
The patch was fine but we can no longer race with SIGKILL after 9899d11f
("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@xxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>
Cc: Michael Neuling <mikey@xxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Prasad <prasad@xxxxxxxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/ptrace.c | 28 +++++-----------------------
1 file changed, 5 insertions(+), 23 deletions(-)
diff -puN arch/x86/kernel/ptrace.c~ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints arch/x86/kernel/ptrace.c
--- a/arch/x86/kernel/ptrace.c~ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints
+++ a/arch/x86/kernel/ptrace.c
@@ -641,9 +641,6 @@ static int ptrace_write_dr7(struct task_
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
unsigned long val = 0;
if (n < HBP_NUM) {
- struct perf_event *bp;
-
- if (ptrace_get_breakpoints(tsk) < 0)
- return -ESRCH;
+ struct perf_event *bp = thread->ptrace_bps[n];
- 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(st
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(st
*/
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(st
attr.bp_addr = addr;
err = modify_user_hw_breakpoint(bp, &attr);
}
-
-put:
- ptrace_put_breakpoints(tsk);
+out:
return err;
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
linux-next.patch
mm-mempolicy-fix-mbind_range-vma_adjust-interaction.patch
include-linux-schedh-dont-use-task-pid-tgid-in-same_thread_group-has_group_leader_pid.patch
lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch
lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch
fput-task_work_add-can-fail-if-the-caller-has-passed-exit_task_work-fix.patch
fput-turn-list_head-delayed_fput_list-into-llist_head.patch
llist-fix-simplify-llist_add-and-llist_add_batch.patch
llist-llist_add-can-use-llist_add_batch.patch
kernel-wide-fix-missing-validations-on-__get-__put-__copy_to-__copy_from_user.patch
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch
signals-eventpoll-set-saved_sigmask-at-the-start.patch
move-exit_task_namespaces-outside-of-exit_notify-fix.patch
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