| Message ID | 20240906024201.1214712-3-wangkefeng.wang@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: hwpoison: two more poison recovery | expand |
On 9/5/2024 7:42 PM, Kefeng Wang wrote: > Similar to other poison recovery, use copy_mc_user_highpage() to > avoid potentially kernel panic during copy page in copy_present_page() > from fork, once copy failed due to hwpoison in source page, we need > to break out of copy in copy_pte_range() and release prealloc folio, > so copy_mc_user_highpage() is moved ahead before set *prealloc to NULL. > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > --- > mm/memory.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index d310c073a1b3..6e7b78e49d1a 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -926,8 +926,11 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma > * We have a prealloc page, all good! Take it > * over and copy the page & arm it. > */ > + > + if (copy_mc_user_highpage(&new_folio->page, page, addr, src_vma)) > + return -EHWPOISON; > + > *prealloc = NULL; > - copy_user_highpage(&new_folio->page, page, addr, src_vma); > __folio_mark_uptodate(new_folio); > folio_add_new_anon_rmap(new_folio, dst_vma, addr, RMAP_EXCLUSIVE); > folio_add_lru_vma(new_folio, dst_vma); > @@ -1166,8 +1169,9 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, > /* > * If we need a pre-allocated page for this pte, drop the > * locks, allocate, and try again. > + * If copy failed due to hwpoison in source page, break out. > */ > - if (unlikely(ret == -EAGAIN)) > + if (unlikely(ret == -EAGAIN || ret == -EHWPOISON)) > break; > if (unlikely(prealloc)) { > /* > @@ -1197,7 +1201,7 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, > goto out; > } > entry.val = 0; > - } else if (ret == -EBUSY) { > + } else if (ret == -EBUSY || unlikely(ret == -EHWPOISON)) { > goto out; > } else if (ret == -EAGAIN) { > prealloc = folio_prealloc(src_mm, src_vma, addr, false); Looks good. Reviewed-by: Jane Chu <jane.chu@oracle.com> -jane
On 2024/9/6 10:42, Kefeng Wang wrote: > Similar to other poison recovery, use copy_mc_user_highpage() to > avoid potentially kernel panic during copy page in copy_present_page() > from fork, once copy failed due to hwpoison in source page, we need > to break out of copy in copy_pte_range() and release prealloc folio, > so copy_mc_user_highpage() is moved ahead before set *prealloc to NULL. > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > --- > mm/memory.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index d310c073a1b3..6e7b78e49d1a 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -926,8 +926,11 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma > * We have a prealloc page, all good! Take it > * over and copy the page & arm it. > */ > + > + if (copy_mc_user_highpage(&new_folio->page, page, addr, src_vma)) > + return -EHWPOISON; > + > *prealloc = NULL; > - copy_user_highpage(&new_folio->page, page, addr, src_vma); > __folio_mark_uptodate(new_folio); > folio_add_new_anon_rmap(new_folio, dst_vma, addr, RMAP_EXCLUSIVE); > folio_add_lru_vma(new_folio, dst_vma); > @@ -1166,8 +1169,9 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, > /* > * If we need a pre-allocated page for this pte, drop the > * locks, allocate, and try again. > + * If copy failed due to hwpoison in source page, break out. > */ > - if (unlikely(ret == -EAGAIN)) > + if (unlikely(ret == -EAGAIN || ret == -EHWPOISON)) Will it be better to put checking ret against -EHWPOISON in a new line? -EAGAIN case will enter the loop again but -EHWPOISON case never does. > break; > if (unlikely(prealloc)) { > /* > @@ -1197,7 +1201,7 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, > goto out; > } > entry.val = 0; > - } else if (ret == -EBUSY) { > + } else if (ret == -EBUSY || unlikely(ret == -EHWPOISON)) { The caller of copy_pte_range() always set errno to -ENOMEM. So fork will failed with ENOMEM even if the real cause is failed to copy due to hwpoison in source page. It's a pity. Thanks. .
On 2024/9/10 10:19, Miaohe Lin wrote: > On 2024/9/6 10:42, Kefeng Wang wrote: >> Similar to other poison recovery, use copy_mc_user_highpage() to >> avoid potentially kernel panic during copy page in copy_present_page() >> from fork, once copy failed due to hwpoison in source page, we need >> to break out of copy in copy_pte_range() and release prealloc folio, >> so copy_mc_user_highpage() is moved ahead before set *prealloc to NULL. >> >> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> >> --- >> mm/memory.c | 10 +++++++--- >> 1 file changed, 7 insertions(+), 3 deletions(-) >> >> diff --git a/mm/memory.c b/mm/memory.c >> index d310c073a1b3..6e7b78e49d1a 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -926,8 +926,11 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma >> * We have a prealloc page, all good! Take it >> * over and copy the page & arm it. >> */ >> + >> + if (copy_mc_user_highpage(&new_folio->page, page, addr, src_vma)) >> + return -EHWPOISON; >> + >> *prealloc = NULL; >> - copy_user_highpage(&new_folio->page, page, addr, src_vma); >> __folio_mark_uptodate(new_folio); >> folio_add_new_anon_rmap(new_folio, dst_vma, addr, RMAP_EXCLUSIVE); >> folio_add_lru_vma(new_folio, dst_vma); >> @@ -1166,8 +1169,9 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, >> /* >> * If we need a pre-allocated page for this pte, drop the >> * locks, allocate, and try again. >> + * If copy failed due to hwpoison in source page, break out. >> */ >> - if (unlikely(ret == -EAGAIN)) >> + if (unlikely(ret == -EAGAIN || ret == -EHWPOISON)) > > Will it be better to put checking ret against -EHWPOISON in a new line? -EAGAIN case will enter the > loop again but -EHWPOISON case never does. Maybe not a newline since we will recheck the ret in the below and return directly from copy_present_page(). > >> break; >> if (unlikely(prealloc)) { >> /* >> @@ -1197,7 +1201,7 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, >> goto out; >> } >> entry.val = 0; >> - } else if (ret == -EBUSY) { >> + } else if (ret == -EBUSY || unlikely(ret == -EHWPOISON)) { > > The caller of copy_pte_range() always set errno to -ENOMEM. So fork will failed with ENOMEM even if the real > cause is failed to copy due to hwpoison in source page. It's a pity. Yes, it's not just the new -EHWPOISON, all other errnos(ENOENT/EIO) will be ignored and return -ENOMEM instead. > > Thanks. > .
On 2024/9/10 14:35, Kefeng Wang wrote: > > > On 2024/9/10 10:19, Miaohe Lin wrote: >> On 2024/9/6 10:42, Kefeng Wang wrote: >>> Similar to other poison recovery, use copy_mc_user_highpage() to >>> avoid potentially kernel panic during copy page in copy_present_page() >>> from fork, once copy failed due to hwpoison in source page, we need >>> to break out of copy in copy_pte_range() and release prealloc folio, >>> so copy_mc_user_highpage() is moved ahead before set *prealloc to NULL. >>> >>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> >>> --- >>> mm/memory.c | 10 +++++++--- >>> 1 file changed, 7 insertions(+), 3 deletions(-) >>> >>> diff --git a/mm/memory.c b/mm/memory.c >>> index d310c073a1b3..6e7b78e49d1a 100644 >>> --- a/mm/memory.c >>> +++ b/mm/memory.c >>> @@ -926,8 +926,11 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma >>> * We have a prealloc page, all good! Take it >>> * over and copy the page & arm it. >>> */ >>> + >>> + if (copy_mc_user_highpage(&new_folio->page, page, addr, src_vma)) >>> + return -EHWPOISON; >>> + >>> *prealloc = NULL; >>> - copy_user_highpage(&new_folio->page, page, addr, src_vma); >>> __folio_mark_uptodate(new_folio); >>> folio_add_new_anon_rmap(new_folio, dst_vma, addr, RMAP_EXCLUSIVE); >>> folio_add_lru_vma(new_folio, dst_vma); >>> @@ -1166,8 +1169,9 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, >>> /* >>> * If we need a pre-allocated page for this pte, drop the >>> * locks, allocate, and try again. >>> + * If copy failed due to hwpoison in source page, break out. >>> */ >>> - if (unlikely(ret == -EAGAIN)) >>> + if (unlikely(ret == -EAGAIN || ret == -EHWPOISON)) >> >> Will it be better to put checking ret against -EHWPOISON in a new line? -EAGAIN case will enter the >> loop again but -EHWPOISON case never does. > > Maybe not a newline since we will recheck the ret in the below and return directly from copy_present_page(). Anyway, this patch looks good to me. Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Thanks. .
diff --git a/mm/memory.c b/mm/memory.c index d310c073a1b3..6e7b78e49d1a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -926,8 +926,11 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma * We have a prealloc page, all good! Take it * over and copy the page & arm it. */ + + if (copy_mc_user_highpage(&new_folio->page, page, addr, src_vma)) + return -EHWPOISON; + *prealloc = NULL; - copy_user_highpage(&new_folio->page, page, addr, src_vma); __folio_mark_uptodate(new_folio); folio_add_new_anon_rmap(new_folio, dst_vma, addr, RMAP_EXCLUSIVE); folio_add_lru_vma(new_folio, dst_vma); @@ -1166,8 +1169,9 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, /* * If we need a pre-allocated page for this pte, drop the * locks, allocate, and try again. + * If copy failed due to hwpoison in source page, break out. */ - if (unlikely(ret == -EAGAIN)) + if (unlikely(ret == -EAGAIN || ret == -EHWPOISON)) break; if (unlikely(prealloc)) { /* @@ -1197,7 +1201,7 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, goto out; } entry.val = 0; - } else if (ret == -EBUSY) { + } else if (ret == -EBUSY || unlikely(ret == -EHWPOISON)) { goto out; } else if (ret == -EAGAIN) { prealloc = folio_prealloc(src_mm, src_vma, addr, false);
Similar to other poison recovery, use copy_mc_user_highpage() to avoid potentially kernel panic during copy page in copy_present_page() from fork, once copy failed due to hwpoison in source page, we need to break out of copy in copy_pte_range() and release prealloc folio, so copy_mc_user_highpage() is moved ahead before set *prealloc to NULL. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- mm/memory.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)