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7F953C4CEED; Fri, 8 Aug 2025 11:42:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754653352; bh=+EXwIQbDINd7zs+mcit0rAyRB8QW/lOaVnLZfgR3OU4=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=thXbzi8UdXsRGC6Qoy3VJbFEU21MkSCOaDClxHC2JK1GJZt0rBKoB1Jn+AH6aCiwi b0g+JiFxsmHtOPyVLLIP38MuvNDBW1mHFNFAITJGNoRqJtYvVjkmjm6acnUCnynowh g6z3N7QQLflKhYJYtEJiZG04QlZIGfT09dmtF5670e5T2hm26OfS1CsXEtZzvJw83I w4zxtBzNlzwxi8sqj1C4dwf2LcZKCFKEp9F5c+F6rW5KqqUC9HWONnn97gcslfc0VX +QP/gzK0YMadigtYGs3vb06wIiT9fNCYpkbZ5lkp5/VOcN1BNMPTw9E1lQThAMnU6l PgoVhAgaXBGyg== From: Pratyush Yadav To: Pasha Tatashin Cc: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, changyuanl@google.com, rppt@kernel.org, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, zhangguopeng@kylinos.cn, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com Subject: Re: [PATCH v3 01/30] kho: init new_physxa->phys_bits to fix lockdep In-Reply-To: <20250807014442.3829950-2-pasha.tatashin@soleen.com> References: <20250807014442.3829950-1-pasha.tatashin@soleen.com> <20250807014442.3829950-2-pasha.tatashin@soleen.com> Date: Fri, 08 Aug 2025 13:42:22 +0200 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 3994B180006 X-Stat-Signature: 9o7nkspq5j35qnedrwif5pdo4m5edhsd X-Rspam-User: X-HE-Tag: 1754653353-169818 X-HE-Meta: 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 9rAlNprB OM56B/Rml35MY/oauZEGvIOKArkuEDaLWEyL1WFMzL0HEu2dqee0M1gS6hHRU2wbZDZ3ZtgibvJ+JvVJcY5Gz3/pKt6QEYrD2Fz28KBashL6VRyaE/0OoFD4pCUK+WUV2uNXy5G+V4btMO2ZC1HjaQ3NMCT0J/3YOuoQGapg6q4uzxbPPfCuUx2jyVZXrxYvaCQ3bLcrnmabuN+QyNy/31peCWrnc9R59vLr5cmtO8rOSGejNcs3ySIIsT7q11/SEGIQjCuY6vDD/v5HOmYdjkJGj/UfkNxo+70MB9sKrg8M7FO5mHRiN1mq4sd+UidPVHPMG3godxMgtlLUeKZ82mUQ5EAMwT3JqQos020oz1DZ5WGFqnFsTTNOwCG5FcHESIQfuuRRl6iHK+aF8nQRiv/YmNw== 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: Hi Pasha, On Thu, Aug 07 2025, Pasha Tatashin wrote: > Lockdep shows the following warning: > > INFO: trying to register non-static key. > The code is fine but needs lockdep annotation, or maybe > you didn't initialize this object before use? > turning off the locking correctness validator. > > [] dump_stack_lvl+0x66/0xa0 > [] assign_lock_key+0x10c/0x120 > [] register_lock_class+0xf4/0x2f0 > [] __lock_acquire+0x7f/0x2c40 > [] ? __pfx_hlock_conflict+0x10/0x10 > [] ? native_flush_tlb_global+0x8e/0xa0 > [] ? __flush_tlb_all+0x4e/0xa0 > [] ? __kernel_map_pages+0x112/0x140 > [] ? xa_load_or_alloc+0x67/0xe0 > [] lock_acquire+0xe6/0x280 > [] ? xa_load_or_alloc+0x67/0xe0 > [] _raw_spin_lock+0x30/0x40 > [] ? xa_load_or_alloc+0x67/0xe0 > [] xa_load_or_alloc+0x67/0xe0 > [] kho_preserve_folio+0x90/0x100 > [] __kho_finalize+0xcf/0x400 > [] kho_finalize+0x34/0x70 > > This is becase xa has its own lock, that is not initialized in > xa_load_or_alloc. > > Modifiy __kho_preserve_order(), to properly call > xa_init(&new_physxa->phys_bits); > > Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") > Signed-off-by: Pasha Tatashin > Acked-by: Mike Rapoport (Microsoft) > --- > kernel/kexec_handover.c | 29 +++++++++++++++++++++++++---- > 1 file changed, 25 insertions(+), 4 deletions(-) > > diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c > index e49743ae52c5..6240bc38305b 100644 > --- a/kernel/kexec_handover.c > +++ b/kernel/kexec_handover.c > @@ -144,14 +144,35 @@ static int __kho_preserve_order(struct kho_mem_track *track, unsigned long pfn, > unsigned int order) > { > struct kho_mem_phys_bits *bits; > - struct kho_mem_phys *physxa; > + struct kho_mem_phys *physxa, *new_physxa; > const unsigned long pfn_high = pfn >> order; > > might_sleep(); > > - physxa = xa_load_or_alloc(&track->orders, order, sizeof(*physxa)); > - if (IS_ERR(physxa)) > - return PTR_ERR(physxa); > + physxa = xa_load(&track->orders, order); > + if (!physxa) { > + new_physxa = kzalloc(sizeof(*physxa), GFP_KERNEL); > + if (!new_physxa) > + return -ENOMEM; > + > + xa_init(&new_physxa->phys_bits); > + physxa = xa_cmpxchg(&track->orders, order, NULL, new_physxa, > + GFP_KERNEL); > + if (xa_is_err(physxa)) { > + int err = xa_err(physxa); > + > + xa_destroy(&new_physxa->phys_bits); > + kfree(new_physxa); > + > + return err; > + } > + if (physxa) { > + xa_destroy(&new_physxa->phys_bits); > + kfree(new_physxa); > + } else { > + physxa = new_physxa; > + } I suppose this could be simplified a bit to: err = xa_err(physxa); if (err || physxa) { xa_destroy(&new_physxa->phys_bits); kfree(new_physxa); if (err) return err; } else { physxa = new_physxa; } No strong preference though, so fine either way. Up to you. Reviewed-by: Pratyush Yadav > + } > > bits = xa_load_or_alloc(&physxa->phys_bits, pfn_high / PRESERVE_BITS, > sizeof(*bits)); -- Regards, Pratyush Yadav