From: Dan Williams <dan.j.williams@intel.com>
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, keescook@chromium.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] mm/shuffle: Fix shuffle enable
Date: Tue, 05 Feb 2019 23:12:10 -0800 [thread overview]
Message-ID: <154943713038.3858443.4125180191382062871.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <154943712485.3858443.4491117952728936852.stgit@dwillia2-desk3.amr.corp.intel.com>
The removal of shuffle_store() in v10 of the patch series was prompted
by the review feedback to convert page_alloc_shuffle() to __memint. I
obviously booted a stale kernel build in my tests because
shuffle_store() is indeed required:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
#PF error: [INSTR]
PGD 0 P4D 0
Oops: 0010 [#1] SMP PTI
CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc1+ #2867
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20180531_142017-buildhw-08.phx2.fedoraproject.org-1.fc28 04/01/2014
RIP: 0010: (null)
Code: Bad RIP value.
RSP: 0000:ffffffff82603e78 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: cccccccccccccccd
RDX: ffffffff8261d7c0 RSI: ffffffff8244c010 RDI: ffff88843ffe1aaa
RBP: ffff88843ffe1aac R08: ffffffff83486978 R09: 0000000000000000
R10: ffffffff82603e80 R11: 0000000000000048 R12: ffff88843ffe1a97
R13: ffff88843ffe1aaa R14: ffffffff8244c010 R15: 000000000000016d
FS: 0000000000000000(0000) GS:ffff88811be00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000002614000 CR4: 00000000000606b0
Call Trace:
? parse_args+0x170/0x360
? set_init_arg+0x55/0x55
? start_kernel+0x1d8/0x4c4
? set_init_arg+0x55/0x55
? secondary_startup_64+0xa4/0xb0
Reintroduce it and mark it __meminit. Given the sysfs attribute is not
writable it will never be called after init.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
mm/shuffle.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/mm/shuffle.c b/mm/shuffle.c
index 19bbf3e37fb6..3ce12481b1dc 100644
--- a/mm/shuffle.c
+++ b/mm/shuffle.c
@@ -38,7 +38,21 @@ extern int shuffle_show(char *buffer, const struct kernel_param *kp)
return sprintf(buffer, "%c\n", test_bit(SHUFFLE_ENABLE, &shuffle_state)
? 'Y' : 'N');
}
-module_param_call(shuffle, NULL, shuffle_show, &shuffle_param, 0400);
+
+static __meminit int shuffle_store(const char *val,
+ const struct kernel_param *kp)
+{
+ int rc = param_set_bool(val, kp);
+
+ if (rc < 0)
+ return rc;
+ if (shuffle_param)
+ page_alloc_shuffle(SHUFFLE_ENABLE);
+ else
+ page_alloc_shuffle(SHUFFLE_FORCE_DISABLE);
+ return 0;
+}
+module_param_call(shuffle, shuffle_store, shuffle_show, &shuffle_param, 0400);
/*
* For two pages to be swapped in the shuffle, they must be free (on a
next prev parent reply other threads:[~2019-02-06 7:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-06 7:12 [PATCH 0/2] mm/shuffle: Fix + default enable Dan Williams
2019-02-06 7:12 ` Dan Williams [this message]
2019-02-06 7:12 ` [PATCH 2/2] [-mm only] mm/shuffle: Default enable all shuffling Dan Williams
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