On Tue, Jul 25, 2023 at 11:57:22PM -0700, syzbot wrote: > syzbot has bisected this issue to: FWIW, this is unrelated to the previous issue. It's the caller of mas_walk() that has violated the locking constraints, and mas_walk() is simply reporting the issue. Is there a way to get syzbot to understand that it needs to unwind the call-stack further to decide who to blame? > commit a52f58b34afe095ebc5823684eb264404dad6f7b > Author: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> > Date: Mon Jul 24 18:54:10 2023 +0000 > > mm: handle faults that merely update the accessed bit under the VMA lock > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1783585ea80000 > start commit: [unknown] > git tree: linux-next > final oops: https://syzkaller.appspot.com/x/report.txt?x=1443585ea80000 > console output: https://syzkaller.appspot.com/x/log.txt?x=1043585ea80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f481ab36ce878b84 > dashboard link: https://syzkaller.appspot.com/bug?extid=8645fe63c4d22c8d27b8 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1697cec9a80000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1566986ea80000 #syz test diff --git a/mm/memory.c b/mm/memory.c index 20a2e9ed4aeb..57b271108bdc 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3567,6 +3567,12 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) return 0; } copy: + if ((vmf->flags & FAULT_FLAG_VMA_LOCK) && !vma->anon_vma) { + pte_unmap_unlock(vmf->pte, vmf->ptl); + vma_end_read(vmf->vma); + return VM_FAULT_RETRY; + } + /* * Ok, we need to copy. Oh, well.. */
