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AJvYcCVnpFcl/GinNqPlbU39+LUZGysD9ReQ7A44BPb+auhGrKQBFMfgozTHknbuf3jxwjJjZxiaX0V5Fg==@kvack.org X-Gm-Message-State: AOJu0YyhkB2EaYnQbEl3oZ1uz1UYDieGE5cra7v/p11UCinaSQAgJlkb eg4DxdYoUziycrsN8f/Cl3/oiYB1TTP2Zo48LeFZtuEC4STzj6TyYfxxW2zOx3j4kNy33e/mlpq l2PvXCWDRtfRPRdRVqyK79k97090bgY/P0gHXqd/COQ== X-Gm-Gg: ASbGncsDwngZ4ie7DAW2+KfZgGanzv0OnYVnWRaYDLy22W7MyvnaHJLaWLaz7YuQdA0 HP5nVMP6a4b2UcN/JhfwMem3OJfPNlLpHPksG6HSYbO6gMEzkr0W/S+8ogZQU7Gwn+Bvu1mn6Bb OPjS4saKH7XCuCA/pY2XPl4ag7M2Yh8iTKttKaNkIQchFn5fXCI6AjK4yOzN0FL1M5HWmoJ36GI MTsH7oBlkl+bHZBqY5vhP0s3CVTj6M3BkwGLzxOTJZ6u0Ab/ASLYxO/jA== X-Google-Smtp-Source: AGHT+IFs9fzvpDPTsAFkSsf2g/axFVw0DqyasrrSTQmpvxxJwCZ/vRFmpg1oJNrPGFoNM0eCGfjdIow3KjiQqmHQR+M= X-Received: by 2002:a05:6402:84d:b0:63c:3f02:60e7 with SMTP id 4fb4d7f45d1cf-641470a5b83mr1085673a12.17.1762514173924; Fri, 07 Nov 2025 03:16:13 -0800 (PST) MIME-Version: 1.0 References: <20251106220635.2608494-1-pasha.tatashin@soleen.com> In-Reply-To: From: Pasha Tatashin Date: Fri, 7 Nov 2025 06:15:37 -0500 X-Gm-Features: AWmQ_bl_5IdSL2Kur2Xuap5Ta8FwDqfYQlgqfAVhcx3fkqLwvwkzYlLkk7DO3Lw Message-ID: Subject: Re: [PATCH] lib/test_kho: Check if KHO is enabled To: Pratyush Yadav Cc: akpm@linux-foundation.org, rppt@kernel.org, graf@amazon.com, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: F1F83C000C X-Stat-Signature: 5wiuibpb8zwaj3pjfmeipx7kudqfpe67 X-Rspam-User: X-HE-Tag: 1762514175-879228 X-HE-Meta: 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 1bf+iVUr 0ZHuS37lNiZVO90r0GG89SpSoj3tQGppL64FPN8ctsKzGNyeeHNhTkhBtYu78KeOxqsjbP5AYTlyYHvNx2U0Np0tEFQnGyP5MKYePJ8nTMJsQteDF+X4IBHDv0Ot76M7Hn8bwNeEnniTpUSNCMsG6tvF4iNyG6fpaUQmVXlzhtdHn7S69GMOnKqTxLit60U+eev30qQeJImUpwrR+Lw/NOXHO/nn/9VM+Qjyqils/Gj7gGqDE+3ltfNHS9R3fiTS1mpsWA1mVZd3DHSylEdtN9D2h25KT+6Qe/xzkLPbqMDSroCl0QRMCyiW3gV0PlaB/zue8gG/pOX5aM05F2igXXmCJIw== 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 Fri, Nov 7, 2025 at 5:24=E2=80=AFAM Pratyush Yadav = wrote: > > On Thu, Nov 06 2025, Pasha Tatashin wrote: > > > We must check whether KHO is enabled prior to issuing KHO commands, > > otherwise KHO internal data structures are not initialized. > > Should we have this check in the KHO APIs instead? This check is easy > enough to miss. I considered adding a kho_is_enabled() check to every KHO API, but it seems unnecessary. In-kernel users of KHO, like reserve_mem and the upcoming LUO, are already expected to check if KHO is enabled before doing extra preservation work. I anticipate any future in-kernel users will follow the same pattern. We could add a WARN_ON(!kho_is_enabled()) to the internal API calls, but I don't think it's needed. We already catch this condition with other WARN_ONs, as shown by this report. > > > > > Fixes: b753522bed0b ("kho: add test for kexec handover") > > > > Nit: these blank lines would probably mess up trailer parsing for > tooling. Hm, if so, the blank line should be removed. Thank you, Pasha > > > Reported-by: kernel test robot > > Closes: https://lore.kernel.org/oe-lkp/202511061629.e242724-lkp@intel.c= om > > > > Signed-off-by: Pasha Tatashin > > --- > > lib/test_kho.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/lib/test_kho.c b/lib/test_kho.c > > index 025ea251a186..85b60d87a50a 100644 > > --- a/lib/test_kho.c > > +++ b/lib/test_kho.c > > @@ -315,6 +315,9 @@ static int __init kho_test_init(void) > > phys_addr_t fdt_phys; > > int err; > > > > + if (!kho_is_enabled()) > > + return 0; > > + > > err =3D kho_retrieve_subtree(KHO_TEST_FDT, &fdt_phys); > > if (!err) > > return kho_test_restore(fdt_phys); > > -- > Regards, > Pratyush Yadav