When hot removing memory presented at boot time, following messages are shown:
[ 296.867031] ------------[ cut here ]------------
[ 296.922273] kernel BUG at mm/slub.c:3409!
[ 296.970229] invalid opcode: 0000 [#1] SMP
[ 297.019453] Modules linked in: ebtable_nat ebtables xt_CHECKSUM iptable_mangle bridge stp llc ipmi_devintf ipmi_msghandler sunrpc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables binfmt_misc vfat fat dm_mirror dm_region_hash dm_log dm_mod vhost_net macvtap macvlan tun uinput iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode pcspkr sg i2c_i801 lpc_ich mfd_core igb i2c_algo_bit i2c_core e1000e ptp pps_core tpm_infineon ioatdma dca sr_mod cdrom sd_mod crc_t10dif usb_storage megaraid_sas lpfc scsi_transport_fc scsi_tgt scsi_mod
[ 297.747808] CPU 0
[ 297.769764] Pid: 5091, comm: kworker/0:2 Tainted: G W 3.9.0-rc6+ #15
[ 297.897917] RIP: 0010:[<ffffffff811c41d2>] [<ffffffff811c41d2>] kfree+0x232/0x240
[ 297.988634] RSP: 0018:ffff88084678d968 EFLAGS: 00010246
[ 298.052196] RAX: 0060000000000400 RBX: ffff8987fffffea0 RCX: 0000000000000000
[ 298.137595] RDX: ffffffff8107a5ae RSI: 0000000000000001 RDI: ffff8987fffffea0
[ 298.222994] RBP: ffff88084678d998 R08: 0000000080000200 R09: 0000000000000001
[ 298.308390] R10: 0000000000000000 R11: 0000000000000000 R12: 0000030000000000
[ 298.393792] R13: ffffea061fffffc0 R14: 00000303ffffffff R15: 0000000000000080
[ 298.479190] FS: 0000000000000000(0000) GS:ffff88085aa00000(0000) knlGS:0000000000000000
[ 298.576030] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 298.644791] CR2: 00000000025d3f78 CR3: 0000000001c0c000 CR4: 00000000001407f0
[ 298.730192] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 298.815590] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 298.900997] Process kworker/0:2 (pid: 5091, threadinfo ffff88084678c000, task ffff88083928ca80)
[ 299.005121] Stack:
[ 299.029156] 00000303ffffffff ffff8987fffffea0 0000030000000000 ffff8987fffffe90
[ 299.118116] 00000303ffffffff 0000000000000080 ffff88084678d9c8 ffffffff8107a5d4
[ 299.207084] 0000000030000000 ffff8987fffb2680 0000000000000080 0000000030000000
[ 299.296045] Call Trace:
[ 299.325288] [<ffffffff8107a5d4>] __release_region+0xd4/0xe0
[ 299.393020] [<ffffffff811c96f2>] __remove_pages+0x52/0x110
[ 299.459707] [<ffffffff816ada89>] arch_remove_memory+0x89/0xd0
[ 299.529505] [<ffffffff816aec94>] remove_memory+0xc4/0x100
[ 299.595145] [<ffffffff814103c5>] acpi_memory_device_remove+0x6d/0xb1
[ 299.672230] [<ffffffff813cbfe3>] acpi_device_remove+0x89/0xab
[ 299.742033] [<ffffffff81479f4c>] __device_release_driver+0x7c/0xf0
[ 299.817048] [<ffffffff8147a0cf>] device_release_driver+0x2f/0x50
[ 299.889972] [<ffffffff813cce98>] acpi_bus_device_detach+0x6c/0x70
[ 299.963938] [<ffffffff813f80f6>] acpi_ns_walk_namespace+0x11a/0x250
[ 300.039982] [<ffffffff813cce2c>] ? power_state_show+0x36/0x36
[ 300.109800] [<ffffffff813cce2c>] ? power_state_show+0x36/0x36
[ 300.179612] [<ffffffff813f874d>] acpi_walk_namespace+0xee/0x137
[ 300.251492] [<ffffffff813ccecf>] acpi_bus_trim+0x33/0x7a
[ 300.316089] [<ffffffff816c182a>] ? mutex_lock_nested+0x4a/0x60
[ 300.386927] [<ffffffff813cdca6>] acpi_bus_hot_remove_device+0xc4/0x1a1
[ 300.466096] [<ffffffff813c8009>] acpi_os_execute_deferred+0x27/0x34
[ 300.542137] [<ffffffff81093467>] process_one_work+0x1f7/0x590
[ 300.611940] [<ffffffff810933f5>] ? process_one_work+0x185/0x590
[ 300.683823] [<ffffffff81094bba>] worker_thread+0x11a/0x370
[ 300.750502] [<ffffffff81094aa0>] ? manage_workers+0x180/0x180
[ 300.820308] [<ffffffff8109adfe>] kthread+0xee/0x100
[ 300.879714] [<ffffffff810e139b>] ? __lock_release+0x12b/0x190
[ 300.949512] [<ffffffff8109ad10>] ? __init_kthread_worker+0x70/0x70
[ 301.024517] [<ffffffff816cf32c>] ret_from_fork+0x7c/0xb0
[ 301.089135] [<ffffffff8109ad10>] ? __init_kthread_worker+0x70/0x70
[ 301.164138] Code: 89 ef e8 c2 2c fb ff e9 0b ff ff ff 4d 8b 6d 30 e9 5c fe ff ff 4c 89 f1 48 89 da 4c 89 ee 4c 89 e7 e8 03 f9 ff ff e9 ec fe ff ff <0f> 0b eb fe 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 48 83 ec
[ 301.397214] RIP [<ffffffff811c41d2>] kfree+0x232/0x240
[ 301.459855] RSP <ffff88084678d968>
[ 301.501675] ---[ end trace 8679967aa8606ed8 ]---
The reason why the messages are shown is to release a resource structure,
allocated by bootmem, by kfree(). So when we release a resource structure,
we should check whether it is allocated by bootmem or not.
But even if we know a resource structure is allocated by bootmem, we cannot
release it since SLxB cannot treat it. So for reusing a resource structure,
this patch remembers it by using bootmem_resource as follows:
When releasing a resource structure by free_resource(), free_resource() checks
whether the resource structure is allocated by bootmem or not. If it is
allocated by bootmem, free_resource() adds it to bootmem_resource. If it is
not allocated by bootmem, free_resource() release it by kfree().
And when getting a new resource structure by get_resource(), get_resource()
checks whether bootmem_resource has released resource structures or not. If
there is a released resource structure, get_resource() returns it. If there is
not a releaed resource structure, get_resource() returns new resource structure
allocated by kzalloc().
Signed-off-by: Yasuaki Ishimatsu <[email protected]>
---
This patch is baseg on following Toshi's works:
Support memory hot-delete to boot memory
https://lkml.org/lkml/2013/4/10/469
kernel/resource.c | 72 +++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 59 insertions(+), 13 deletions(-)
diff --git a/kernel/resource.c b/kernel/resource.c
index 16bfd39..152e9aa 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -21,6 +21,7 @@
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/pfn.h>
+#include <linux/mm.h>
#include <asm/io.h>
@@ -50,6 +51,16 @@ struct resource_constraint {
static DEFINE_RWLOCK(resource_lock);
+/*
+ * For memory hotplug, there is no way to free resource entries allocated
+ * by boot mem after the system is up. So for reusing the resource entry
+ * we need to remember the resource.
+ */
+struct resource bootmem_resource = {
+ .sibling = NULL,
+};
+static DEFINE_SPINLOCK(bootmem_resource_lock);
+
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
@@ -151,6 +162,42 @@ __initcall(ioresources_init);
#endif /* CONFIG_PROC_FS */
+static void __free_resource(struct resource *res)
+{
+ struct resource *next_res = bootmem_resource.sibling;
+
+ bootmem_resource.sibling = res;
+ res->sibling = next_res;
+}
+
+static void free_resource(struct resource *res)
+{
+ if (PageReserved(virt_to_page(res))) {
+ spin_lock(&bootmem_resource_lock);
+ __free_resource(res);
+ spin_unlock(&bootmem_resource_lock);
+ } else {
+ kfree(res);
+ }
+}
+
+static struct resource *get_resource(gfp_t flags)
+{
+ struct resource *res;
+
+ if (bootmem_resource.sibling) {
+ spin_lock(&bootmem_resource_lock);
+ res = bootmem_resource.sibling;
+ bootmem_resource.sibling = res->sibling;
+ spin_unlock(&bootmem_resource_lock);
+ memset(res, 0, sizeof(struct resource));
+ } else {
+ res = kzalloc(sizeof(struct resource), flags);
+ }
+
+ return res;
+}
+
/* Return the conflict entry if you can't request it */
static struct resource * __request_resource(struct resource *root, struct resource *new)
{
@@ -771,7 +818,7 @@ static void __init __reserve_region_with_split(struct resource *root,
{
struct resource *parent = root;
struct resource *conflict;
- struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
+ struct resource *res = get_resource(GFP_ATOMIC);
struct resource *next_res = NULL;
if (!res)
@@ -796,7 +843,7 @@ static void __init __reserve_region_with_split(struct resource *root,
/* conflict covered whole area */
if (conflict->start <= res->start &&
conflict->end >= res->end) {
- kfree(res);
+ free_resource(res);
WARN_ON(next_res);
break;
}
@@ -806,10 +853,9 @@ static void __init __reserve_region_with_split(struct resource *root,
end = res->end;
res->end = conflict->start - 1;
if (conflict->end < end) {
- next_res = kzalloc(sizeof(*next_res),
- GFP_ATOMIC);
+ next_res = get_resource(GFP_ATOMIC);
if (!next_res) {
- kfree(res);
+ free_resource(res);
break;
}
next_res->name = name;
@@ -899,7 +945,7 @@ struct resource * __request_region(struct resource *parent,
const char *name, int flags)
{
DECLARE_WAITQUEUE(wait, current);
- struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
+ struct resource *res = get_resource(GFP_KERNEL);
if (!res)
return NULL;
@@ -933,7 +979,7 @@ struct resource * __request_region(struct resource *parent,
continue;
}
/* Uhhuh, that didn't work out.. */
- kfree(res);
+ free_resource(res);
res = NULL;
break;
}
@@ -967,7 +1013,7 @@ int __check_region(struct resource *parent, resource_size_t start,
return -EBUSY;
release_resource(res);
- kfree(res);
+ free_resource(res);
return 0;
}
EXPORT_SYMBOL(__check_region);
@@ -1007,7 +1053,7 @@ void __release_region(struct resource *parent, resource_size_t start,
write_unlock(&resource_lock);
if (res->flags & IORESOURCE_MUXED)
wake_up(&muxed_resource_wait);
- kfree(res);
+ free_resource(res);
return;
}
p = &res->sibling;
@@ -1055,8 +1101,8 @@ int release_mem_region_adjustable(struct resource *parent,
if ((start < parent->start) || (end > parent->end))
return ret;
- /* The kzalloc() result gets checked later */
- new_res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+ /* The get_resource() result gets checked later */
+ new_res = get_resource(GFP_KERNEL);
p = &parent->child;
write_lock(&resource_lock);
@@ -1083,7 +1129,7 @@ int release_mem_region_adjustable(struct resource *parent,
if (res->start == start && res->end == end) {
/* free the whole entry */
*p = res->sibling;
- kfree(res);
+ free_resource(res);
ret = 0;
} else if (res->start == start && res->end != end) {
/* adjust the start */
@@ -1119,7 +1165,7 @@ int release_mem_region_adjustable(struct resource *parent,
}
write_unlock(&resource_lock);
- kfree(new_res);
+ free_resource(new_res);
return ret;
}
#endif /* CONFIG_MEMORY_HOTPLUG */
On Mon, 2013-04-15 at 11:15 +0900, Yasuaki Ishimatsu wrote:
> When hot removing memory presented at boot time, following messages are shown:
:
> The reason why the messages are shown is to release a resource structure,
> allocated by bootmem, by kfree(). So when we release a resource structure,
> we should check whether it is allocated by bootmem or not.
>
> But even if we know a resource structure is allocated by bootmem, we cannot
> release it since SLxB cannot treat it. So for reusing a resource structure,
> this patch remembers it by using bootmem_resource as follows:
>
> When releasing a resource structure by free_resource(), free_resource() checks
> whether the resource structure is allocated by bootmem or not. If it is
> allocated by bootmem, free_resource() adds it to bootmem_resource. If it is
> not allocated by bootmem, free_resource() release it by kfree().
>
> And when getting a new resource structure by get_resource(), get_resource()
> checks whether bootmem_resource has released resource structures or not. If
> there is a released resource structure, get_resource() returns it. If there is
> not a releaed resource structure, get_resource() returns new resource structure
> allocated by kzalloc().
Thanks for fixing this existing issue that also needed to be addressed.
I am not able to test this particular case in my test env, so I did not
notice it.
Can you update this patch to base off of the patch below? Otherwise, it
won't apply cleanly.
https://lkml.org/lkml/2013/4/11/694
More comments below.
> Signed-off-by: Yasuaki Ishimatsu <[email protected]>
> ---
> This patch is baseg on following Toshi's works:
> Support memory hot-delete to boot memory
> https://lkml.org/lkml/2013/4/10/469
>
> kernel/resource.c | 72 +++++++++++++++++++++++++++++++++++++++++++---------
> 1 files changed, 59 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/resource.c b/kernel/resource.c
> index 16bfd39..152e9aa 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -21,6 +21,7 @@
> #include <linux/seq_file.h>
> #include <linux/device.h>
> #include <linux/pfn.h>
> +#include <linux/mm.h>
> #include <asm/io.h>
>
>
> @@ -50,6 +51,16 @@ struct resource_constraint {
>
> static DEFINE_RWLOCK(resource_lock);
>
> +/*
> + * For memory hotplug, there is no way to free resource entries allocated
> + * by boot mem after the system is up. So for reusing the resource entry
> + * we need to remember the resource.
> + */
> +struct resource bootmem_resource = {
> + .sibling = NULL,
> +};
> +static DEFINE_SPINLOCK(bootmem_resource_lock);
> +
> static void *r_next(struct seq_file *m, void *v, loff_t *pos)
> {
> struct resource *p = v;
> @@ -151,6 +162,42 @@ __initcall(ioresources_init);
>
> #endif /* CONFIG_PROC_FS */
>
> +static void __free_resource(struct resource *res)
> +{
> + struct resource *next_res = bootmem_resource.sibling;
> +
> + bootmem_resource.sibling = res;
> + res->sibling = next_res;
> +}
> +
> +static void free_resource(struct resource *res)
> +{
You need to add the following if-statement here. Otherwise it hits a
page fault when res is NULL. This case happens when a resource entry
splits into two entries.
if (!res)
return;
> + if (PageReserved(virt_to_page(res))) {
> + spin_lock(&bootmem_resource_lock);
> + __free_resource(res);
How about simply updating the link here, instead of having it done in
__free_resource()? I think it makes it more consistent with
get_resource().
res->sibling = bootmem_resource.sibling;
bootmem_resource.sibling = res;
Thanks,
-Toshi
> + spin_unlock(&bootmem_resource_lock);
> + } else {
> + kfree(res);
> + }
> +}
Hi Toshi,
2013/04/16 5:01, Toshi Kani wrote:
> On Mon, 2013-04-15 at 11:15 +0900, Yasuaki Ishimatsu wrote:
>> When hot removing memory presented at boot time, following messages are shown:
>
> :
>
>> The reason why the messages are shown is to release a resource structure,
>> allocated by bootmem, by kfree(). So when we release a resource structure,
>> we should check whether it is allocated by bootmem or not.
>>
>> But even if we know a resource structure is allocated by bootmem, we cannot
>> release it since SLxB cannot treat it. So for reusing a resource structure,
>> this patch remembers it by using bootmem_resource as follows:
>>
>> When releasing a resource structure by free_resource(), free_resource() checks
>> whether the resource structure is allocated by bootmem or not. If it is
>> allocated by bootmem, free_resource() adds it to bootmem_resource. If it is
>> not allocated by bootmem, free_resource() release it by kfree().
>>
>> And when getting a new resource structure by get_resource(), get_resource()
>> checks whether bootmem_resource has released resource structures or not. If
>> there is a released resource structure, get_resource() returns it. If there is
>> not a releaed resource structure, get_resource() returns new resource structure
>> allocated by kzalloc().
>
> Thanks for fixing this existing issue that also needed to be addressed.
> I am not able to test this particular case in my test env, so I did not
> notice it.
>
> Can you update this patch to base off of the patch below? Otherwise, it
> won't apply cleanly.
> https://lkml.org/lkml/2013/4/11/694
O.K. I'll update it.
>
> More comments below.
>
>> Signed-off-by: Yasuaki Ishimatsu <[email protected]>
>> ---
>> This patch is baseg on following Toshi's works:
>> Support memory hot-delete to boot memory
>> https://lkml.org/lkml/2013/4/10/469
>>
>> kernel/resource.c | 72 +++++++++++++++++++++++++++++++++++++++++++---------
>> 1 files changed, 59 insertions(+), 13 deletions(-)
>>
>> diff --git a/kernel/resource.c b/kernel/resource.c
>> index 16bfd39..152e9aa 100644
>> --- a/kernel/resource.c
>> +++ b/kernel/resource.c
>> @@ -21,6 +21,7 @@
>> #include <linux/seq_file.h>
>> #include <linux/device.h>
>> #include <linux/pfn.h>
>> +#include <linux/mm.h>
>> #include <asm/io.h>
>>
>>
>> @@ -50,6 +51,16 @@ struct resource_constraint {
>>
>> static DEFINE_RWLOCK(resource_lock);
>>
>> +/*
>> + * For memory hotplug, there is no way to free resource entries allocated
>> + * by boot mem after the system is up. So for reusing the resource entry
>> + * we need to remember the resource.
>> + */
>> +struct resource bootmem_resource = {
>> + .sibling = NULL,
>> +};
>> +static DEFINE_SPINLOCK(bootmem_resource_lock);
>> +
>> static void *r_next(struct seq_file *m, void *v, loff_t *pos)
>> {
>> struct resource *p = v;
>> @@ -151,6 +162,42 @@ __initcall(ioresources_init);
>>
>> #endif /* CONFIG_PROC_FS */
>>
>> +static void __free_resource(struct resource *res)
>> +{
>> + struct resource *next_res = bootmem_resource.sibling;
>> +
>> + bootmem_resource.sibling = res;
>> + res->sibling = next_res;
>> +}
>> +
>> +static void free_resource(struct resource *res)
>> +{
>
> You need to add the following if-statement here. Otherwise it hits a
> page fault when res is NULL. This case happens when a resource entry
> splits into two entries.
>
> if (!res)
> return;
I'll update it.
>
>> + if (PageReserved(virt_to_page(res))) {
>> + spin_lock(&bootmem_resource_lock);
>> + __free_resource(res);
>
> How about simply updating the link here, instead of having it done in
> __free_resource()? I think it makes it more consistent with
> get_resource().
>
> res->sibling = bootmem_resource.sibling;
> bootmem_resource.sibling = res;
I'll update it.
Thanks,
Yasuaki Ishimatsu
>
> Thanks,
> -Toshi
>
>> + spin_unlock(&bootmem_resource_lock);
>> + } else {
>> + kfree(res);
>> + }
>> +}
>
>
>
> -----Original Message-----
> From: Yasuaki Ishimatsu <[email protected]>
> Date: Mon, 15 Apr 2013 11:15:28 +0900
> Subject: [Bug fix PATCH] resource: Reusing a resource structure allocated by
> bootmem
> To: [email protected]
> Cc: [email protected], [email protected], [email protected],
> [email protected], Yasuaki Ishimatsu <[email protected]>
> <<...>>
> + if (bootmem_resource.sibling) {
> + spin_lock(&bootmem_resource_lock);
> + res = bootmem_resource.sibling;
> + bootmem_resource.sibling = res->sibling;
> + spin_unlock(&bootmem_resource_lock);
> + memset(res, 0, sizeof(struct resource));
> + } else {
> + res = kzalloc(sizeof(struct resource), flags);
> + }
bootmem_resource_lock does not protect the if() statement from accessing bootmem_resource.sibling.
spin_lock(&bootmem_resource_lock);
if (bootmem_resource.sibling) {
...
Rui
Hi Rui,
Thank you for your review.
2013/04/16 17:17, Wang, Rui Y wrote:
>> -----Original Message-----
>> From: Yasuaki Ishimatsu <[email protected]>
>> Date: Mon, 15 Apr 2013 11:15:28 +0900
>> Subject: [Bug fix PATCH] resource: Reusing a resource structure allocated by
>> bootmem
>> To: [email protected]
>> Cc: [email protected], [email protected], [email protected],
>> [email protected], Yasuaki Ishimatsu <[email protected]>
>> <<...>>
>> + if (bootmem_resource.sibling) {
>> + spin_lock(&bootmem_resource_lock);
>> + res = bootmem_resource.sibling;
>> + bootmem_resource.sibling = res->sibling;
>> + spin_unlock(&bootmem_resource_lock);
>> + memset(res, 0, sizeof(struct resource));
>> + } else {
>> + res = kzalloc(sizeof(struct resource), flags);
>> + }
>
> bootmem_resource_lock does not protect the if() statement from accessing bootmem_resource.sibling.
>
> spin_lock(&bootmem_resource_lock);
> if (bootmem_resource.sibling) {
You are right. I'll update it.
Thanks,
Yasuaki Ishimatsu
> ...
>
> Rui
>