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charset=us-ascii Content-Disposition: inline X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 86E81100006 X-Stat-Signature: djfmw3oet8dcsgqd81hmj8oip1wojren X-HE-Tag: 1684920730-725376 X-HE-Meta: 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 DCCPomHh 7/ZyYIwH6IMun5YLemadllGCvNMcMbm1AdwAebiyjw2fKqMN0CH32dzbPAF1k8iH2j22HeTXyULubWkr8gUHwVgjyUoYTnrWyGDwbiYAJiRa7b3Kwy5P57rqAc+DdVPON41iQp4ujo51kskWwli+KtzSfniJlyUcWxGRBJuknGCyYOEzE65ntYCzvPuiVCpR3K8S8EEjRZr8/U+4= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 05/23/23 at 04:02pm, Thomas Gleixner wrote: > _vm_unmap_aliases() is used to ensure that no unflushed TLB entries for a > page are left in the system. This is required due to the lazy TLB flush > mechanism in vmalloc. > > This is tried to achieve by walking the per CPU free lists, but those do > not contain fully utilized vmap blocks because they are removed from the > free list once the blocks free space became zero. > > So the per CPU list iteration does not find the block and if the page was > mapped via such a block and the TLB has not yet been flushed, the guarantee > of _vm_unmap_aliases() that there are no stale TLBs after returning is > broken: > > x = vb_alloc() // Removes vmap_block from free list because vb->free became 0 > vb_free(x) // Unmaps page and marks in dirty_min/max range > > // Page is reused > vm_unmap_aliases() // Can't find vmap block with the dirty space -> FAIL > > So instead of walking the per CPU free lists, walk the per CPU xarrays > which hold pointers to _all_ active blocks in the system including those > removed from the free lists. > > Signed-off-by: Thomas Gleixner > --- > mm/vmalloc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2236,9 +2236,10 @@ static void _vm_unmap_aliases(unsigned l > for_each_possible_cpu(cpu) { > struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu); > struct vmap_block *vb; > + unsigned long idx; > > rcu_read_lock(); Do we need to remove this rcu_read_xx() pair since it marks the RCU read-side critical section on vbq-free list? > - list_for_each_entry_rcu(vb, &vbq->free, free_list) { > + xa_for_each(&vbq->vmap_blocks, idx, vb) { > spin_lock(&vb->lock); > if (vb->dirty && vb->dirty != VMAP_BBMAP_BITS) { > unsigned long va_start = vb->va->va_start; >