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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: <5vif6anhufcalcsrsmlmhssxzajd5jo4ztnnnuoqvdfwjta6vq@6yvfxq6fci22> 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-Queue-Id: B9FF5180008 X-Stat-Signature: ea5dej9k76zq1bmt9sjur65mgf9biosy X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1768986449-81674 X-HE-Meta: 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 oBJJuHsf SwYfxZTXZcsrYbp3OWqs2TjTO3/WJNy5A2PgUp8YEOGcodUCr8OMSOQ3ELk30Io42TQiv6ImYN09IE2JuOpNvSXUJwEibgb8CKs1/0/y5duzXJUWWKRWpnRaeWmNBGS48eF2W5sZQdDtF8HMXgG9t+vXwObWpbIBDsYlL0SKHTrNqRZUfxmozHu2MiXspWyu49Yz/FRI0Mip9hPk/SVy0om8lnos9NWlrIXmGgfZjjTPOuJVP2Ss2V3LR/nQvHSKEHqVaMA8RvFhPO5kBVuGS2WCyvgs1ZOXBsk/fCqq95Ny5gpZvMcQh8ZmY4zcRAb4eQcz//3vpXh/6TeOJ2DRIAgKY1PDFHOvcDJMMpyghOIzlrYWgrifIe7iNNglt1EkgphyrHw0grJ/T1MFXkSQo+Sz4qA== 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. RCU warn is not always trigger-able, sometimes it's might_sleep assertion: [ 1.593114][ T136] BUG: sleeping function called from invalid context at ./include/linux/sched/mm.h:323 [ 1.595588][ C0] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000087: 0000 [#1] SMP KASAN [ 1.596578][ C0] KASAN: null-ptr-deref in range [0x0000000000000438-0x000000000000043f] [ 1.596578][ C0] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.19.0-rc6-next-20260120-00004-g7dff00c348a6 #676 PREEMPT [ 1.596578][ C0] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.1 11/11/2019 [ 1.596578][ C0] RIP: 0010:select_task_rq_fair+0x520/0x810 [..]