3.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tang Chen <tangchen@xxxxxxxxxxxxxx>
commit dee1592638ab7ea35a32179b73f9284dead49c03 upstream.
When ACPI_HOTPLUG_MEMORY is not configured, memory_device_handler.attach
is not set. In acpi_scan_attach_handler(), the acpi_device->handler will
not be initialized.
In acpi_scan_hot_remove(), it doesn't check if acpi_device->handler is NULL.
If we do memory hot-remove without ACPI_HOTPLUG_MEMORY configured, the kernel
will panic.
BUG: unable to handle kernel NULL pointer dereference at 0000000000000088
IP: [<ffffffff813e318f>] acpi_device_hotplug+0x1d7/0x4c4
PGD 0
Oops: 0000 [#1] SMP
Modules linked in: sd_mod(E) sr_mod(E) cdrom(E) crc_t10dif(E) crct10dif_common(E) ata_piix(E) libata(E)
CPU: 0 PID: 41 Comm: kworker/u2:1 Tainted: G E 3.16.0-rc7--3.16-rc7-tangchen+ #20
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
Workqueue: kacpi_hotplug acpi_hotplug_work_fn
task: ffff8800182436c0 ti: ffff880018254000 task.ti: ffff880018254000
RIP: 0010:[<ffffffff813e318f>] [<ffffffff813e318f>] acpi_device_hotplug+0x1d7/0x4c4
RSP: 0000:ffff880018257da8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88001cd8d800 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88001e40e6f8 RDI: 0000000000000246
RBP: ffff880018257df0 R08: 0000000000000096 R09: 00000000000011a0
R10: 63735f6970636120 R11: 725f746f685f6e61 R12: 0000000000000003
R13: ffff88001cc1c400 R14: ffff88001e062028 R15: 0000000000000040
FS: 0000000000000000(0000) GS:ffff88001e400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000088 CR3: 000000001a9a2000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 0000000000000000 DR7: 0000000000000000
Stack:
00000000523cab58 ffff88001cd8d9f8 ffff88001852d480 00000000523cab58
ffff88001852d480 ffff880018221e40 ffff88001cc1c400 ffff88001cce2d00
0000000000000040 ffff880018257e08 ffffffff813dc31d ffff88001852d480
Call Trace:
[<ffffffff813dc31d>] acpi_hotplug_work_fn+0x1e/0x29
[<ffffffff8108eefb>] process_one_work+0x17b/0x460
[<ffffffff8108f69d>] worker_thread+0x11d/0x5b0
[<ffffffff8108f580>] ? rescuer_thread+0x3a0/0x3a0
[<ffffffff81096811>] kthread+0xe1/0x100
[<ffffffff81096730>] ? kthread_create_on_node+0x1a0/0x1a0
[<ffffffff816cc6bc>] ret_from_fork+0x7c/0xb0
[<ffffffff81096730>] ? kthread_create_on_node+0x1a0/0x1a0
This patch fixes this problem by checking if acpi_device->handler is NULL
in acpi_scan_hot_remove().
Fixes: d22ddcbc4fb7 (ACPI / hotplug: Add demand_offline hotplug profile flag)
Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
[rjw: Subject]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/acpi/scan.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -351,7 +351,8 @@ static int acpi_scan_hot_remove(struct a
unsigned long long sta;
acpi_status status;
- if (device->handler->hotplug.demand_offline && !acpi_force_hot_remove) {
+ if (device->handler && device->handler->hotplug.demand_offline
+ && !acpi_force_hot_remove) {
if (!acpi_scan_is_offline(device, true))
return -EBUSY;
} else {
--
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