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McKenney" Cc: Sergey Senozhatsky , Peter Zijlstra , Thomas Gleixner , Andrew Morton , Steven Rostedt , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [next-20260120] KASAN: maybe wild-memory-access in select_task_rq_fair Message-ID: References: <3e3af3b6-28fe-448f-90f1-4f2ed0c651f4@paulmck-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3e3af3b6-28fe-448f-90f1-4f2ed0c651f4@paulmck-laptop> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: DD4C0100003 X-Stat-Signature: eszyhexn6fa6e83bpdbdy5t84essec1h X-Rspam-User: X-HE-Tag: 1768986119-927473 X-HE-Meta: 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 LJ8+Zgzc h4HMGX1z4rG7s63HMIPhFSXpKvnKmKsR0YPS6gb5JrFn4yEkNL3hTejCdMP38biSGGVp5ih/qvS1X0qvplQBoKgV7xWHtCwejjRd1/0LmKpKp4M8/18QO3+n39nc7bwHAWwdoJWz5Y/YGrQxJTISibGVrHQ== 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 (26/01/20 21:11), Paul E. McKenney wrote: > On Wed, Jan 21, 2026 at 01:03:02PM +0900, Sergey Senozhatsky wrote: > > Hello, > > > > I'm seeing the following KASAN report on next-20260120 (qemu x86_64). > > There seems to be a lot of stuff going on in the call trace: > > I'll say! > > > [ 1.714941][ T136] ================================================================== > > [ 1.715713][ C0] Oops: general protection fault, probably for non-canonical address 0xeb1125008e9810b0: 0000 [#1] SMP KASAN > > [ 1.715702][ T136] ------------[ cut here ]------------ > > [ 1.716702][ C0] KASAN: maybe wild-memory-access in range [0x5889480474c08580-0x5889480474c08587] > > [ 1.716702][ C0] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.19.0-rc6-next-20260120-00004-g7dff00c348a6 #645 PREEMPT > > [ 1.715702][ T136] WARNING: kernel/rcu/tree_plugin.h:443 at __rcu_read_unlock+0xb6/0xe0, CPU#2: devtmpf.X/136 > > This is most likely to happen when you do an rcu_read_unlock() > without a matchine rcu_read_lock(). It could also happen if you > nested rcu_read_lock() a billion deep. Or if RCU had a strange > bug. Or if someone corrupted the current task_struct structure's > =>rcu_read_lock_nesting field. > > Is it feasible to bisect this? I started bisect, but due to circumstances won't be done today (most likely will continue tomorrow).