RE: [PATCH 1/1] resource: Fixed iomem resource release failed on release_mem_region_adjustable() when memory node or cpu node hot-remove.
From: Guomin Chen
Date: Sat Jun 23 2018 - 01:53:59 EST
Hi
The report link for this issue is: https://bugzilla.suse.com/show_bug.cgi?id=1092687
Thanks and regards
> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas@xxxxxxxxxx]
> Sent: 2018年6月23日 7:20
> To: Guomin Chen <guomin.chen@xxxxxxxx>
> Cc: Brijesh Singh <brijesh.singh@xxxxxxx>; Tom Lendacky
> <thomas.lendacky@xxxxxxx>; Yaowei Bai
> <baiyaowei@xxxxxxxxxxxxxxxxxxxx>; Bjorn Helgaas <bhelgaas@xxxxxxxxxx>;
> Toshi Kani <toshi.kani@xxxxxxx>; Dan Williams <dan.j.williams@xxxxxxxxx>;
> Thomas Gleixner <tglx@xxxxxxxxxxxxx>; Andrew Morton
> <akpm@xxxxxxxxxxxxxxxxxxxx>; Joey Lee <JLee@xxxxxxxx>; Borislav Petkov
> <bp@xxxxxxx>; Takashi Iwai <tiwai@xxxxxxx>; linux-efi@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 1/1] resource: Fixed iomem resource release failed on
> release_mem_region_adjustable() when memory node or cpu node
> hot-remove.
>
> [+cc Toshi]
>
> On Fri, Jun 22, 2018 at 08:01:38PM +0800, guomin chen wrote:
> > We've got a bug report indicating the hot-remove node resource release
> > failed,when the memory on this node is divided into several
> > sections.because the release_mem_region_adjustable() can only release
> > one resource that must be [start,end].
>
> Can you please include a URL for the bug report? That's useful for additional
> details and gives hints about how future changes in this area might be tested.
>
> release_mem_region_adjustable() and the only call to it were added by Toshi
> (cc'd):
>
> 825f787bb496 ("resource: add release_mem_region_adjustable()")
> fe74ebb106a5 ("mm: change __remove_pages() to call
> release_mem_region_adjustable()")
>
> > In my case, the BIOS supports faulty memory isolation. if BIOS
> > detected bad memory block, the BIOS will isolates this badblock.
> > And set this badblock memory to EfiUnusableMemory in EFI memory map
> > base on UEFI 2.7 spec.For example in my system, the memory range on
> > node2 is [mem 0x0000080000000000-0x00000807ffffffff].but the BIOS
> > detected the [8004e000000-8004e0fffff] is a badblock memory.
> > So the memory on node2 seem like this:
> > 80000000000-8004dffffff : System RAM
> > 8004e000000-8004e0fffff : Unusable memory
> > 8004e100000-807ffffffff : System RAM
> >
> > Now, when offline the cpu node2,the kernel will try to release
> > ioresource [mem 0x0000080000000000-0x00000807ffffffff]. at this time,
> > the kernel will release failed,and output error message:
> > "Unable to release resource <0x0000080000000000-0x00000807ffffffff>
> > (-22)".
> > Because the release_mem_region_adjustable() can only release one
> > resource that must be [0x0000080000000000 , 0x00000807ffffffff].
> > but now,the iomem resource on node2 [0x0000080000000000,
> > 0x00000807ffffffff] are divided into three resources [80000000000-
> > 8004dffffff],[8004e000000-8004e0fffff]and[8004e100000-807ffffffff].
> >
> > This patch help to Release multiple iomem resources at once when node
> > hot-remove. Such as in above case, when hot-remove the cpu node2,the
> > kernel will try to release resource [0x0000080000000000-
> > 0x00000807ffffffff].And this patch will release three resources
> > [80000000000-8004dffffff],[8004e000000-8004e0fffff] and
> > [8004e100000-807ffffffff].
> >
> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > Cc: Brijesh Singh <brijesh.singh@xxxxxxx>
> > Cc: Borislav Petkov <bp@xxxxxxx>
> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Cc: Yaowei Bai <baiyaowei@xxxxxxxxxxxxxxxxxxxx>
> > Cc: Takashi Iwai <tiwai@xxxxxxx>
> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> > Cc: linux-efi@xxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Cc: Lee Chun-Yi <JLee@xxxxxxxx>
> > Signed-off-by: guomin chen <guomin.chen@xxxxxxxx>
> > ---
> > kernel/resource.c | 73
> > ++++++++++++++++++++++++++++++++-----------------------
> > 1 file changed, 43 insertions(+), 30 deletions(-)
> >
> > diff --git a/kernel/resource.c b/kernel/resource.c index
> > 30e1bc68503b..959bcce4c405 100644
> > --- a/kernel/resource.c
> > +++ b/kernel/resource.c
> > @@ -1240,6 +1240,7 @@ int release_mem_region_adjustable(struct
> resource *parent,
> > struct resource *res;
> > struct resource *new_res;
> > resource_size_t end;
> > + resource_size_t new_start = start;
> > int ret = -EINVAL;
> >
> > end = start + size - 1;
> > @@ -1257,7 +1258,7 @@ int release_mem_region_adjustable(struct
> resource *parent,
> > break;
> >
> > /* look for the next resource if it does not fit into */
> > - if (res->start > start || res->end < end) {
> > + if (res->end < new_start) {
> > p = &res->sibling;
> > continue;
> > }
> > @@ -1271,42 +1272,54 @@ int release_mem_region_adjustable(struct
> resource *parent,
> > }
> >
> > /* found the target resource; let's adjust accordingly */
> > - if (res->start == start && res->end == end) {
> > + if (res->start == new_start && res->end == end) {
> > /* free the whole entry */
> > *p = res->sibling;
> > free_resource(res);
> > ret = 0;
> > - } else if (res->start == start && res->end != end) {
> > - /* adjust the start */
> > - ret = __adjust_resource(res, end + 1,
> > - res->end - end);
> > - } else if (res->start != start && res->end == end) {
> > - /* adjust the end */
> > - ret = __adjust_resource(res, res->start,
> > - start - res->start);
> > + } else if (res->end > end) {
> > + if (res->start >= new_start) {
> > + /* adjust the start */
> > + ret = __adjust_resource(res, end + 1,
> > + res->end - end);
> > + } else {
> > + /* split into two entries */
> > + if (!new_res) {
> > + ret = -ENOMEM;
> > + break;
> > + }
> > + new_res->name = res->name;
> > + new_res->start = end + 1;
> > + new_res->end = res->end;
> > + new_res->flags = res->flags;
> > + new_res->desc = res->desc;
> > + new_res->parent = res->parent;
> > + new_res->sibling = res->sibling;
> > + new_res->child = NULL;
> > +
> > + ret = __adjust_resource(res, res->start,
> > + new_start - res->start);
> > + if (ret)
> > + break;
> > + res->sibling = new_res;
> > + new_res = NULL;
> > + }
> > } else {
> > - /* split into two entries */
> > - if (!new_res) {
> > - ret = -ENOMEM;
> > - break;
> > + if (res->start < new_start) {
> > + /* adjust the end */
> > + ret = __adjust_resource(res, res->start,
> > + new_start - res->start);
> > + new_start = res->end+1;
> > + p = &res->sibling;
> > + } else {
> > + new_start = res->end+1;
> > + *p = res->sibling;
> > + free_resource(res);
> > + ret = 0;
> > }
> > - new_res->name = res->name;
> > - new_res->start = end + 1;
> > - new_res->end = res->end;
> > - new_res->flags = res->flags;
> > - new_res->desc = res->desc;
> > - new_res->parent = res->parent;
> > - new_res->sibling = res->sibling;
> > - new_res->child = NULL;
> > -
> > - ret = __adjust_resource(res, res->start,
> > - start - res->start);
> > - if (ret)
> > - break;
> > - res->sibling = new_res;
> > - new_res = NULL;
> > + if (res->end < end)
> > + continue;
> > }
> > -
> > break;
> > }
> >
> > --
> > 2.12.3
> >