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Howlett" , Lorenzo Stoakes , Vlastimil Babka , Shakeel Butt , Jann Horn , Pedro Falcato , Chris Li Subject: Re: [PATCH 1/2] mm: Add vma_start_write_killable() Message-ID: References: <20251103180348.3368668-1-willy@infradead.org> <20251103180348.3368668-2-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251103180348.3368668-2-willy@infradead.org> X-Stat-Signature: hjqi7ih135cpjnzcfqk4fmcttt8ir43c X-Rspam-User: X-Rspamd-Queue-Id: 837A52000F X-Rspamd-Server: rspam10 X-HE-Tag: 1762272598-697045 X-HE-Meta: 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 E6rL3gtu VfR+RbiqdY2Ukv84ziOCfOATslui6qrxd6LTzZlmlgBlgtIdueYOi64gEzT6ZlFB4paSg9fsh1XsCj+P1/y+29pWM//ns/JS56bx3XY7trAb+SowfPIBt43IIHb5mJlpnJWjIhC36rMwjp60XQOFQnzl4k5nCDTHGHcRdPcj5Ymgg1k9GV3py/vhFVfOA2CkJzDwSk/zGOZZbUOcJDoG3vn1QZV9N15Vw0Rfgmu+YP6D2syBFrChHifdUD+NMprn4qXygOgGg4RSQ5gJucAO5qVhn3doMbbzJ1a0mA+qGPPFzi2E= 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: List-Subscribe: List-Unsubscribe: On Mon, Nov 03, 2025 at 06:03:45PM +0000, Matthew Wilcox (Oracle) wrote: > @@ -58,15 +60,17 @@ static inline bool __vma_enter_locked(struct vm_area_struct *vma, bool detaching > * vm_refcnt. mmap_write_lock prevents racing with vma_mark_attached(). > */ > if (!refcount_add_not_zero(VMA_LOCK_OFFSET, &vma->vm_refcnt)) > - return false; > + return 0; > > rwsem_acquire(&vma->vmlock_dep_map, 0, 0, _RET_IP_); > - rcuwait_wait_event(&vma->vm_mm->vma_writer_wait, > + err = rcuwait_wait_event(&vma->vm_mm->vma_writer_wait, > refcount_read(&vma->vm_refcnt) == tgt_refcnt, > - TASK_UNINTERRUPTIBLE); > + state); > + if (err) > + return err; > lock_acquired(&vma->vmlock_dep_map, _RET_IP_); > > - return true; > + return 1; I'll wait a couple more days for review before sending v2, but the fix for the syzbot issue is: @@ -66,8 +71,10 @@ static inline int __vma_enter_locked(struct vm_area_struct *vma, err = rcuwait_wait_event(&vma->vm_mm->vma_writer_wait, refcount_read(&vma->vm_refcnt) == tgt_refcnt, state); - if (err) + if (err) { + rwsem_release(&vma->vmlock_dep_map, _RET_IP_); return err; + } lock_acquired(&vma->vmlock_dep_map, _RET_IP_); return 1;