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author | Naoya Horiguchi <nao.horiguchi@gmail.com> | 2020-06-12 03:34:45 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-12 04:17:47 +0300 |
commit | 4e018b450ad34b0edc865e91ec5e957d677e2c4e (patch) | |
tree | 45874bd5f646a255d7fd2f15d63d271807b8c524 /mm | |
parent | 623f6dc593eaf98b91916836785278eddddaacf8 (diff) |
mm/memory-failure: prioritize prctl(PR_MCE_KILL) over vm.memory_failure_early_kill
Patch series "hwpoison: fixes signaling on memory error"
This is a small patchset to solve issues in memory error handler to send
SIGBUS to proper process/thread as expected in configuration. Please
see descriptions in individual patches for more details.
This patch (of 2):
Early-kill policy is controlled from two types of settings, one is
per-process setting prctl(PR_MCE_KILL) and the other is system-wide
setting vm.memory_failure_early_kill. Users expect per-process setting
to override system-wide setting as many other settings do, but
early-kill setting doesn't work as such.
For example, if a system configures vm.memory_failure_early_kill to 1
(enabled), a process receives SIGBUS even if it's configured to
explicitly disable PF_MCE_KILL by prctl(). That's not desirable for
applications with their own policies.
This patch is suggesting to change the priority of these two types of
settings, by checking sysctl_memory_failure_early_kill only when a given
process has the default kill policy.
Note that this patch is solving a thread choice issue too.
Originally, collect_procs() always chooses the main thread when
vm.memory_failure_early_kill is 1, even if the process has a dedicated
thread for memory error handling. SIGBUS should be sent to the
dedicated thread if early-kill is enabled via
vm.memory_failure_early_kill as we are doing for PR_MCE_KILL_EARLY
processes.
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/1591321039-22141-1-git-send-email-naoya.horiguchi@nec.com
Link: http://lkml.kernel.org/r/1591321039-22141-2-git-send-email-naoya.horiguchi@nec.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/memory-failure.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ababa368cb68..848de82cd547 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -402,9 +402,15 @@ static struct task_struct *find_early_kill_thread(struct task_struct *tsk) { struct task_struct *t; - for_each_thread(tsk, t) - if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY)) - return t; + for_each_thread(tsk, t) { + if (t->flags & PF_MCE_PROCESS) { + if (t->flags & PF_MCE_EARLY) + return t; + } else { + if (sysctl_memory_failure_early_kill) + return t; + } + } return NULL; } @@ -417,17 +423,11 @@ static struct task_struct *find_early_kill_thread(struct task_struct *tsk) static struct task_struct *task_early_kill(struct task_struct *tsk, int force_early) { - struct task_struct *t; if (!tsk->mm) return NULL; if (force_early) return tsk; - t = find_early_kill_thread(tsk); - if (t) - return t; - if (sysctl_memory_failure_early_kill) - return tsk; - return NULL; + return find_early_kill_thread(tsk); } /* |