The patch titled
itimers: fix racy writes to cpu_itimer fields
has been added to the -mm tree. Its filename is
itimers-fix-racy-writes-to-cpu_itimer-fields.patch
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Subject: itimers: fix racy writes to cpu_itimer fields
From: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
incr_error and error fields of struct cpu_itimer are used when calculating
next timer tick in check_cpu_itimers() and should not be modified without
tsk->sighand->siglock taken.
Signed-off-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/itimer.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff -puN kernel/itimer.c~itimers-fix-racy-writes-to-cpu_itimer-fields kernel/itimer.c
--- a/kernel/itimer.c~itimers-fix-racy-writes-to-cpu_itimer-fields
+++ a/kernel/itimer.c
@@ -146,6 +146,7 @@ static void set_cpu_itimer(struct task_s
{
cputime_t cval, nval, cinterval, ninterval;
s64 ns_ninterval, ns_nval;
+ u32 error, incr_error;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
nval = timeval_to_cputime(&value->it_value);
@@ -153,8 +154,8 @@ static void set_cpu_itimer(struct task_s
ninterval = timeval_to_cputime(&value->it_interval);
ns_ninterval = timeval_to_ns(&value->it_interval);
- it->incr_error = cputime_sub_ns(ninterval, ns_ninterval);
- it->error = cputime_sub_ns(nval, ns_nval);
+ error = cputime_sub_ns(nval, ns_nval);
+ incr_error = cputime_sub_ns(ninterval, ns_ninterval);
spin_lock_irq(&tsk->sighand->siglock);
@@ -168,6 +169,8 @@ static void set_cpu_itimer(struct task_s
}
it->expires = nval;
it->incr = ninterval;
+ it->error = error;
+ it->incr_error = incr_error;
trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
_
Patches currently in -mm which might be from sgruszka@xxxxxxxxxx are
itimers-fix-racy-writes-to-cpu_itimer-fields.patch
posix-cpu-timers-initialize-new_itimer-itcpufiring.patch
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