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authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-25 18:43:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-25 18:43:59 -0700
commit2923b27e54242acf27fd16b299e102117c82f52f (patch)
tree86b3e27575814dab74307a7928bf579455b70e24 /mm
parent828bf6e904eb8fc8969333568802689fbbf07a40 (diff)
parentc953cc987ab87d180e1d5de2f1c217abe33aac77 (diff)
downloadlinux-stericsson-2923b27e54242acf27fd16b299e102117c82f52f.tar.gz
Merge tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm memory-failure update from Dave Jiang: "As it stands, memory_failure() gets thoroughly confused by dev_pagemap backed mappings. The recovery code has specific enabling for several possible page states and needs new enabling to handle poison in dax mappings. In order to support reliable reverse mapping of user space addresses: 1/ Add new locking in the memory_failure() rmap path to prevent races that would typically be handled by the page lock. 2/ Since dev_pagemap pages are hidden from the page allocator and the "compound page" accounting machinery, add a mechanism to determine the size of the mapping that encompasses a given poisoned pfn. 3/ Given pmem errors can be repaired, change the speculatively accessed poison protection, mce_unmap_kpfn(), to be reversible and otherwise allow ongoing access from the kernel. A side effect of this enabling is that MADV_HWPOISON becomes usable for dax mappings, however the primary motivation is to allow the system to survive userspace consumption of hardware-poison via dax. Specifically the current behavior is: mce: Uncorrected hardware memory error in user-access at af34214200 {1}[Hardware Error]: It has been corrected by h/w and requires no further action mce: [Hardware Error]: Machine check events logged {1}[Hardware Error]: event severity: corrected Memory failure: 0xaf34214: reserved kernel page still referenced by 1 users [..] Memory failure: 0xaf34214: recovery action for reserved kernel page: Failed mce: Memory error not recovered <reboot> ...and with these changes: Injecting memory failure for pfn 0x20cb00 at process virtual address 0x7f763dd00000 Memory failure: 0x20cb00: Killing dax-pmd:5421 due to hardware memory corruption Memory failure: 0x20cb00: recovery action for dax page: Recovered Given all the cross dependencies I propose taking this through nvdimm.git with acks from Naoya, x86/core, x86/RAS, and of course dax folks" * tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm: libnvdimm, pmem: Restore page attributes when clearing errors x86/memory_failure: Introduce {set, clear}_mce_nospec() x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses mm, memory_failure: Teach memory_failure() about dev_pagemap pages filesystem-dax: Introduce dax_lock_mapping_entry() mm, memory_failure: Collect mapping size in collect_procs() mm, madvise_inject_error: Let memory_failure() optionally take a page reference mm, dev_pagemap: Do not clear ->mapping on final put mm, madvise_inject_error: Disable MADV_SOFT_OFFLINE for ZONE_DEVICE pages filesystem-dax: Set page->index device-dax: Set page->index device-dax: Enable page_mapping() device-dax: Convert to vmf_insert_mixed and vm_fault_t
Diffstat (limited to 'mm')
-rw-r--r--mm/hmm.c2
-rw-r--r--mm/huge_memory.c4
-rw-r--r--mm/madvise.c16
-rw-r--r--mm/memory-failure.c210
4 files changed, 186 insertions, 46 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index 0b0554591610..c968e49f7a0c 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -968,6 +968,8 @@ static void hmm_devmem_free(struct page *page, void *data)
{
struct hmm_devmem *devmem = data;
+ page->mapping = NULL;
+
devmem->ops->free(devmem, page);
}
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 08b544383d74..c3bc7e9c9a2a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -752,7 +752,7 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
spin_unlock(ptl);
}
-int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
+vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd, pfn_t pfn, bool write)
{
pgprot_t pgprot = vma->vm_page_prot;
@@ -812,7 +812,7 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
spin_unlock(ptl);
}
-int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
+vm_fault_t vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
pud_t *pud, pfn_t pfn, bool write)
{
pgprot_t pgprot = vma->vm_page_prot;
diff --git a/mm/madvise.c b/mm/madvise.c
index 4d3c922ea1a1..972a9eaa898b 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -631,11 +631,13 @@ static int madvise_inject_error(int behavior,
for (; start < end; start += PAGE_SIZE << order) {
+ unsigned long pfn;
int ret;
ret = get_user_pages_fast(start, 1, 0, &page);
if (ret != 1)
return ret;
+ pfn = page_to_pfn(page);
/*
* When soft offlining hugepages, after migrating the page
@@ -651,17 +653,25 @@ static int madvise_inject_error(int behavior,
if (behavior == MADV_SOFT_OFFLINE) {
pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
- page_to_pfn(page), start);
+ pfn, start);
ret = soft_offline_page(page, MF_COUNT_INCREASED);
if (ret)
return ret;
continue;
}
+
pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
- page_to_pfn(page), start);
+ pfn, start);
- ret = memory_failure(page_to_pfn(page), MF_COUNT_INCREASED);
+ /*
+ * Drop the page reference taken by get_user_pages_fast(). In
+ * the absence of MF_COUNT_INCREASED the memory_failure()
+ * routine is responsible for pinning the page to prevent it
+ * from being released back to the page allocator.
+ */
+ put_page(page);
+ ret = memory_failure(pfn, 0);
if (ret)
return ret;
}
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 192d0bbfc9ea..0cd3de3550f0 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -55,6 +55,7 @@
#include <linux/hugetlb.h>
#include <linux/memory_hotplug.h>
#include <linux/mm_inline.h>
+#include <linux/memremap.h>
#include <linux/kfifo.h>
#include <linux/ratelimit.h>
#include <linux/page-isolation.h>
@@ -175,22 +176,51 @@ int hwpoison_filter(struct page *p)
EXPORT_SYMBOL_GPL(hwpoison_filter);
/*
+ * Kill all processes that have a poisoned page mapped and then isolate
+ * the page.
+ *
+ * General strategy:
+ * Find all processes having the page mapped and kill them.
+ * But we keep a page reference around so that the page is not
+ * actually freed yet.
+ * Then stash the page away
+ *
+ * There's no convenient way to get back to mapped processes
+ * from the VMAs. So do a brute-force search over all
+ * running processes.
+ *
+ * Remember that machine checks are not common (or rather
+ * if they are common you have other problems), so this shouldn't
+ * be a performance issue.
+ *
+ * Also there are some races possible while we get from the
+ * error detection to actually handle it.
+ */
+
+struct to_kill {
+ struct list_head nd;
+ struct task_struct *tsk;
+ unsigned long addr;
+ short size_shift;
+ char addr_valid;
+};
+
+/*
* Send all the processes who have the page mapped a signal.
* ``action optional'' if they are not immediately affected by the error
* ``action required'' if error happened in current execution context
*/
-static int kill_proc(struct task_struct *t, unsigned long addr,
- unsigned long pfn, struct page *page, int flags)
+static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags)
{
- short addr_lsb;
+ struct task_struct *t = tk->tsk;
+ short addr_lsb = tk->size_shift;
int ret;
pr_err("Memory failure: %#lx: Killing %s:%d due to hardware memory corruption\n",
pfn, t->comm, t->pid);
- addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT;
if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) {
- ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)addr,
+ ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)tk->addr,
addr_lsb, current);
} else {
/*
@@ -199,7 +229,7 @@ static int kill_proc(struct task_struct *t, unsigned long addr,
* This could cause a loop when the user sets SIGBUS
* to SIG_IGN, but hopefully no one will do that?
*/
- ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)addr,
+ ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)tk->addr,
addr_lsb, t); /* synchronous? */
}
if (ret < 0)
@@ -235,34 +265,39 @@ void shake_page(struct page *p, int access)
}
EXPORT_SYMBOL_GPL(shake_page);
-/*
- * Kill all processes that have a poisoned page mapped and then isolate
- * the page.
- *
- * General strategy:
- * Find all processes having the page mapped and kill them.
- * But we keep a page reference around so that the page is not
- * actually freed yet.
- * Then stash the page away
- *
- * There's no convenient way to get back to mapped processes
- * from the VMAs. So do a brute-force search over all
- * running processes.
- *
- * Remember that machine checks are not common (or rather
- * if they are common you have other problems), so this shouldn't
- * be a performance issue.
- *
- * Also there are some races possible while we get from the
- * error detection to actually handle it.
- */
-
-struct to_kill {
- struct list_head nd;
- struct task_struct *tsk;
- unsigned long addr;
- char addr_valid;
-};
+static unsigned long dev_pagemap_mapping_shift(struct page *page,
+ struct vm_area_struct *vma)
+{
+ unsigned long address = vma_address(page, vma);
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ pgd = pgd_offset(vma->vm_mm, address);
+ if (!pgd_present(*pgd))
+ return 0;
+ p4d = p4d_offset(pgd, address);
+ if (!p4d_present(*p4d))
+ return 0;
+ pud = pud_offset(p4d, address);
+ if (!pud_present(*pud))
+ return 0;
+ if (pud_devmap(*pud))
+ return PUD_SHIFT;
+ pmd = pmd_offset(pud, address);
+ if (!pmd_present(*pmd))
+ return 0;
+ if (pmd_devmap(*pmd))
+ return PMD_SHIFT;
+ pte = pte_offset_map(pmd, address);
+ if (!pte_present(*pte))
+ return 0;
+ if (pte_devmap(*pte))
+ return PAGE_SHIFT;
+ return 0;
+}
/*
* Failure handling: if we can't find or can't kill a process there's
@@ -293,6 +328,10 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
}
tk->addr = page_address_in_vma(p, vma);
tk->addr_valid = 1;
+ if (is_zone_device_page(p))
+ tk->size_shift = dev_pagemap_mapping_shift(p, vma);
+ else
+ tk->size_shift = compound_order(compound_head(p)) + PAGE_SHIFT;
/*
* In theory we don't have to kill when the page was
@@ -300,7 +339,7 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
* likely very rare kill anyways just out of paranoia, but use
* a SIGKILL because the error is not contained anymore.
*/
- if (tk->addr == -EFAULT) {
+ if (tk->addr == -EFAULT || tk->size_shift == 0) {
pr_info("Memory failure: Unable to find user space address %lx in %s\n",
page_to_pfn(p), tsk->comm);
tk->addr_valid = 0;
@@ -318,9 +357,8 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
* Also when FAIL is set do a force kill because something went
* wrong earlier.
*/
-static void kill_procs(struct list_head *to_kill, int forcekill,
- bool fail, struct page *page, unsigned long pfn,
- int flags)
+static void kill_procs(struct list_head *to_kill, int forcekill, bool fail,
+ unsigned long pfn, int flags)
{
struct to_kill *tk, *next;
@@ -343,8 +381,7 @@ static void kill_procs(struct list_head *to_kill, int forcekill,
* check for that, but we need to tell the
* process anyways.
*/
- else if (kill_proc(tk->tsk, tk->addr,
- pfn, page, flags) < 0)
+ else if (kill_proc(tk, pfn, flags) < 0)
pr_err("Memory failure: %#lx: Cannot send advisory machine check signal to %s:%d\n",
pfn, tk->tsk->comm, tk->tsk->pid);
}
@@ -516,6 +553,7 @@ static const char * const action_page_types[] = {
[MF_MSG_TRUNCATED_LRU] = "already truncated LRU page",
[MF_MSG_BUDDY] = "free buddy page",
[MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)",
+ [MF_MSG_DAX] = "dax page",
[MF_MSG_UNKNOWN] = "unknown page",
};
@@ -1013,7 +1051,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
* any accesses to the poisoned memory.
*/
forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL);
- kill_procs(&tokill, forcekill, !unmap_success, p, pfn, flags);
+ kill_procs(&tokill, forcekill, !unmap_success, pfn, flags);
return unmap_success;
}
@@ -1113,6 +1151,83 @@ out:
return res;
}
+static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
+ struct dev_pagemap *pgmap)
+{
+ struct page *page = pfn_to_page(pfn);
+ const bool unmap_success = true;
+ unsigned long size = 0;
+ struct to_kill *tk;
+ LIST_HEAD(tokill);
+ int rc = -EBUSY;
+ loff_t start;
+
+ /*
+ * Prevent the inode from being freed while we are interrogating
+ * the address_space, typically this would be handled by
+ * lock_page(), but dax pages do not use the page lock. This
+ * also prevents changes to the mapping of this pfn until
+ * poison signaling is complete.
+ */
+ if (!dax_lock_mapping_entry(page))
+ goto out;
+
+ if (hwpoison_filter(page)) {
+ rc = 0;
+ goto unlock;
+ }
+
+ switch (pgmap->type) {
+ case MEMORY_DEVICE_PRIVATE:
+ case MEMORY_DEVICE_PUBLIC:
+ /*
+ * TODO: Handle HMM pages which may need coordination
+ * with device-side memory.
+ */
+ goto unlock;
+ default:
+ break;
+ }
+
+ /*
+ * Use this flag as an indication that the dax page has been
+ * remapped UC to prevent speculative consumption of poison.
+ */
+ SetPageHWPoison(page);
+
+ /*
+ * Unlike System-RAM there is no possibility to swap in a
+ * different physical page at a given virtual address, so all
+ * userspace consumption of ZONE_DEVICE memory necessitates
+ * SIGBUS (i.e. MF_MUST_KILL)
+ */
+ flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
+ collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED);
+
+ list_for_each_entry(tk, &tokill, nd)
+ if (tk->size_shift)
+ size = max(size, 1UL << tk->size_shift);
+ if (size) {
+ /*
+ * Unmap the largest mapping to avoid breaking up
+ * device-dax mappings which are constant size. The
+ * actual size of the mapping being torn down is
+ * communicated in siginfo, see kill_proc()
+ */
+ start = (page->index << PAGE_SHIFT) & ~(size - 1);
+ unmap_mapping_range(page->mapping, start, start + size, 0);
+ }
+ kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
+ rc = 0;
+unlock:
+ dax_unlock_mapping_entry(page);
+out:
+ /* drop pgmap ref acquired in caller */
+ put_dev_pagemap(pgmap);
+ action_result(pfn, MF_MSG_DAX, rc ? MF_FAILED : MF_RECOVERED);
+ return rc;
+}
+
/**
* memory_failure - Handle memory failure of a page.
* @pfn: Page Number of the corrupted page
@@ -1135,6 +1250,7 @@ int memory_failure(unsigned long pfn, int flags)
struct page *p;
struct page *hpage;
struct page *orig_head;
+ struct dev_pagemap *pgmap;
int res;
unsigned long page_flags;
@@ -1147,6 +1263,10 @@ int memory_failure(unsigned long pfn, int flags)
return -ENXIO;
}
+ pgmap = get_dev_pagemap(pfn, NULL);
+ if (pgmap)
+ return memory_failure_dev_pagemap(pfn, flags, pgmap);
+
p = pfn_to_page(pfn);
if (PageHuge(p))
return memory_failure_hugetlb(pfn, flags);
@@ -1777,6 +1897,14 @@ int soft_offline_page(struct page *page, int flags)
int ret;
unsigned long pfn = page_to_pfn(page);
+ if (is_zone_device_page(page)) {
+ pr_debug_ratelimited("soft_offline: %#lx page is device page\n",
+ pfn);
+ if (flags & MF_COUNT_INCREASED)
+ put_page(page);
+ return -EIO;
+ }
+
if (PageHWPoison(page)) {
pr_info("soft offline: %#lx page already poisoned\n", pfn);
if (flags & MF_COUNT_INCREASED)