| Message ID | 20231116201547.536857-3-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/pagemap: A few fixes to the recent PAGEMAP_SCAN | expand |
On 16.11.23 21:15, Peter Xu wrote: > The new pagemap ioctl contains a fast path for wr-protections without > looking into category masks. It forgets to check PM_SCAN_WP_MATCHING > before applying the wr-protections. It can cause, e.g., pte markers > installed on archs that do not even support uffd wr-protect. > > WARNING: CPU: 0 PID: 5059 at mm/memory.c:1520 zap_pte_range mm/memory.c:1520 [inline] > > Fixes: 12f6b01a0bcb ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag") > Reported-by: syzbot+7ca4b2719dc742b8d0a4@syzkaller.appspotmail.com > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > fs/proc/task_mmu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index e91085d79926..d19924bf0a39 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -2171,7 +2171,7 @@ static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start, > return 0; > } > > - if (!p->vec_out) { > + if ((p->arg.flags & PM_SCAN_WP_MATCHING) && !p->vec_out) { > /* Fast path for performing exclusive WP */ > for (addr = start; addr != end; pte++, addr += PAGE_SIZE) { > if (pte_uffd_wp(ptep_get(pte))) Reviewed-by: David Hildenbrand <david@redhat.com>
On Thu, Nov 16, 2023 at 12:15 PM Peter Xu <peterx@redhat.com> wrote: > > The new pagemap ioctl contains a fast path for wr-protections without > looking into category masks. It forgets to check PM_SCAN_WP_MATCHING > before applying the wr-protections. It can cause, e.g., pte markers > installed on archs that do not even support uffd wr-protect. > > WARNING: CPU: 0 PID: 5059 at mm/memory.c:1520 zap_pte_range mm/memory.c:1520 [inline] > > Fixes: 12f6b01a0bcb ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag") > Reported-by: syzbot+7ca4b2719dc742b8d0a4@syzkaller.appspotmail.com > Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Andrei Vagin <avagin@gmail.com> > --- > fs/proc/task_mmu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index e91085d79926..d19924bf0a39 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -2171,7 +2171,7 @@ static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start, > return 0; > } > > - if (!p->vec_out) { > + if ((p->arg.flags & PM_SCAN_WP_MATCHING) && !p->vec_out) { > /* Fast path for performing exclusive WP */ > for (addr = start; addr != end; pte++, addr += PAGE_SIZE) { > if (pte_uffd_wp(ptep_get(pte))) > -- > 2.41.0 >
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index e91085d79926..d19924bf0a39 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -2171,7 +2171,7 @@ static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start, return 0; } - if (!p->vec_out) { + if ((p->arg.flags & PM_SCAN_WP_MATCHING) && !p->vec_out) { /* Fast path for performing exclusive WP */ for (addr = start; addr != end; pte++, addr += PAGE_SIZE) { if (pte_uffd_wp(ptep_get(pte)))
The new pagemap ioctl contains a fast path for wr-protections without looking into category masks. It forgets to check PM_SCAN_WP_MATCHING before applying the wr-protections. It can cause, e.g., pte markers installed on archs that do not even support uffd wr-protect. WARNING: CPU: 0 PID: 5059 at mm/memory.c:1520 zap_pte_range mm/memory.c:1520 [inline] Fixes: 12f6b01a0bcb ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag") Reported-by: syzbot+7ca4b2719dc742b8d0a4@syzkaller.appspotmail.com Signed-off-by: Peter Xu <peterx@redhat.com> --- fs/proc/task_mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)