4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Borislav Petkov <bp@xxxxxxx>
commit 12e26969b32c79018165d52caff3762135614aa1 upstream.
I get the splat below when modprobing/rmmoding EDAC drivers. It happens
because bus->name is invalid after bus_unregister() has run. The Code: section
below corresponds to:
.loc 1 1108 0
movq 672(%rbx), %rax # mci_1(D)->bus, mci_1(D)->bus
.loc 1 1109 0
popq %rbx #
.loc 1 1108 0
movq (%rax), %rdi # _7->name,
jmp kfree #
and %rax has some funky stuff 2030203020312030 which looks a lot like
something walked over it.
Fix that by saving the name ptr before doing stuff to string it points to.
general protection fault: 0000 [#1] SMP
Modules linked in: ...
CPU: 4 PID: 10318 Comm: modprobe Tainted: G I EN 3.12.51-11-default+ #48
Hardware name: HP ProLiant DL380 G7, BIOS P67 05/05/2011
task: ffff880311320280 ti: ffff88030da3e000 task.ti: ffff88030da3e000
RIP: 0010:[<ffffffffa019da92>] [<ffffffffa019da92>] edac_unregister_sysfs+0x22/0x30 [edac_core]
RSP: 0018:ffff88030da3fe28 EFLAGS: 00010292
RAX: 2030203020312030 RBX: ffff880311b4e000 RCX: 000000000000095c
RDX: 0000000000000001 RSI: ffff880327bb9600 RDI: 0000000000000286
RBP: ffff880311b4e750 R08: 0000000000000000 R09: ffffffff81296110
R10: 0000000000000400 R11: 0000000000000000 R12: ffff88030ba1ac68
R13: 0000000000000001 R14: 00000000011b02f0 R15: 0000000000000000
FS: 00007fc9bf8f5700(0000) GS:ffff8801a7c40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000403c90 CR3: 000000019ebdf000 CR4: 00000000000007e0
Stack:
Call Trace:
i7core_unregister_mci.isra.9
i7core_remove
pci_device_remove
__device_release_driver
driver_detach
bus_remove_driver
pci_unregister_driver
i7core_exit
SyS_delete_module
system_call_fastpath
0x7fc9bf426536
Code: 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 53 48 89 fb e8 52 2a 1f e1 48 8b bb a0 02 00 00 e8 46 59 1f e1 48 8b 83 a0 02 00 00 5b <48> 8b 38 e9 26 9a fe e0 66 0f 1f 44 00 00 66 66 66 66 90 48 8b
RIP [<ffffffffa019da92>] edac_unregister_sysfs+0x22/0x30 [edac_core]
RSP <ffff88030da3fe28>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
Fixes: 7a623c039075 ("edac: rewrite the sysfs code to use struct device")
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/edac/edac_mc_sysfs.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -880,21 +880,26 @@ static struct device_type mci_attr_type
int edac_create_sysfs_mci_device(struct mem_ctl_info *mci,
const struct attribute_group **groups)
{
+ char *name;
int i, err;
/*
* The memory controller needs its own bus, in order to avoid
* namespace conflicts at /sys/bus/edac.
*/
- mci->bus->name = kasprintf(GFP_KERNEL, "mc%d", mci->mc_idx);
- if (!mci->bus->name)
+ name = kasprintf(GFP_KERNEL, "mc%d", mci->mc_idx);
+ if (!name)
return -ENOMEM;
+ mci->bus->name = name;
+
edac_dbg(0, "creating bus %s\n", mci->bus->name);
err = bus_register(mci->bus);
- if (err < 0)
- goto fail_free_name;
+ if (err < 0) {
+ kfree(name);
+ return err;
+ }
/* get the /sys/devices/system/edac subsys reference */
mci->dev.type = &mci_attr_type;
@@ -961,8 +966,8 @@ fail_unregister_dimm:
device_unregister(&mci->dev);
fail_unregister_bus:
bus_unregister(mci->bus);
-fail_free_name:
- kfree(mci->bus->name);
+ kfree(name);
+
return err;
}
@@ -993,10 +998,12 @@ void edac_remove_sysfs_mci_device(struct
void edac_unregister_sysfs(struct mem_ctl_info *mci)
{
+ const char *name = mci->bus->name;
+
edac_dbg(1, "Unregistering device %s\n", dev_name(&mci->dev));
device_unregister(&mci->dev);
bus_unregister(mci->bus);
- kfree(mci->bus->name);
+ kfree(name);
}
static void mc_attr_release(struct device *dev)
--
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