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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: MW4PR12MB7213.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: e64c2b95-514b-4383-73f5-08de16995d59 X-MS-Exchange-CrossTenant-originalarrivaltime: 29 Oct 2025 03:15:08.5046 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: z/gfYyXRtDdKK5WAmHsurhYHyxc6xmeW74LliUHj8JqHV7ldOfadFGDQ1FWwJfadg3Mr2evTTnACLNHC/dFgJA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV3PR12MB9215 X-Rspamd-Queue-Id: 537CB180007 X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: doxnsjkojybf4w7jx9dfmo73pjs7aawg X-HE-Tag: 1761707713-32609 X-HE-Meta: U2FsdGVkX1/y0PfymgqHPT67xL/NlEe4idYu9acq9kSydjtB7sBPj9r8dvGF1HL22hXwpYQiB3mvgnt7yjMStEft93oiOJac3VbEfvvl3/J754QXtZj9gPXHmkslgLreOS9jwgOXqANBWPhLrPYSl3sWQROtfhSDlLTrL39+GJ5qqHXO8/oBrnrNndUfNkSQn4oYc1cWbNBH8qbT0+zzgb0lqw1aFQa//epvWhZ8CU02GNktWNqLev66F6WzpTo6pBvMAmDC04OoF1DHVnMMz+KphCdm8BNTgHWxNfrczIwO2a3ZpNx2fJ0kSm5SARxV47TawIr17SdhL8AZFlmeVvnEpum4KwOXJ4JxaYn2RlQrOAro1g0uIurPqJu39z1NoPjTu6BBqLuwz/3ksf/DsmxVHyPyB2QbbHcn7d8K22P3L3xOlqEhDcfrgAYVmiZpgf33VnSQdRR71BI47kRI/peAcPg9zA4hDAYvkqPfP6lUWfVvVYBRgHQNPyykOzpll1M8+0LHJCryt5I7/1vsK9VS9bzij4w28M0YShcQvsrODjGz6v9fEup16pv9a2Bl60jUOrh2pelQbQXeNRcK/LtsIGM0tIHapcbtvOQilgGDmahttrVVLwcze6NY7sWSASeDhCxAKcfbpONvCUTsWjrG7WjhabeyUuH8w4TDEuVPa//CaPGujmYJ7zNz7IhnhDLNipcckLjn99hMXKvSKoaXN8yWdv/BYRG3oIc+eOZfBxcp2mUzMrBKNApxcyaaeUvnZ3jFoLOMfDv4moyoB3kwMW4PhPxlNO6+YGtqTkC6Lhq5/s+ulEtj6E7k1is2O5uzCjb1sNzhIjbMvixsp9PKTL6lgNTdgS6LU6KywO5rYB4+c+cQAcPLKayazquorCrrmcSPcntg8upI1CsorsPSgjD0XpOPrUaSLguqTpHoez3hwqqSTvOXE7FVxX1DgOsNFS7Ze/PmzprvUMZ nl/h6eBH 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 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: Thanks Andrew for the comments.=0A= =0A= >> +int register_pfn_address_space(struct pfn_address_space *pfn_space)=0A= >> +{=0A= >> +=A0=A0=A0=A0 if (!pfn_space)=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 return -EINVAL;=0A= >=0A= > I suggest this be removed - make register_pfn_address_space(NULL)=0A= > illegal and let the punishment be an oops.=0A= =0A= Yes, will remove it.=0A= =0A= >> +static void add_to_kill_pfn(struct task_struct *tsk,=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0 struct vm_area_struct *vma,=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0 struct list_head *to_kill,=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0 unsigned long pfn)=0A= >> +{=0A= >> +=A0=A0=A0=A0 struct to_kill *tk;=0A= >> +=0A= >> +=A0=A0=A0=A0 tk =3D kmalloc(sizeof(*tk), GFP_ATOMIC);=0A= >> +=A0=A0=A0=A0 if (!tk)=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 return;=0A= >=0A= > This is unfortunate.=A0 GFP_ATOMIC is unreliable and we silently behave= =0A= > as if it worked OK.=0A= =0A= Got it. I'll mark this as a failure case.=0A= =0A= =0A= > We could play games here to make the GFP_ATOMIC allocation unnecessary,= =0A= > but nasty.=A0 Allocate the to_kill* outside the rcu_read_lock, pass that= =0A= > pointer into add_to_kill_pfn().=A0 If add_to_kill_pfn()'s=0A= > kmalloc(GFP_ATOMIC) failed, add_to_kill_pfn() can then consume the=0A= > caller's to_kill*.=A0 Then the caller can drop the lock, allocate a new= =0A= > to_kill* then restart the scan.=A0 And teach add_to_kill_pfn() to not=0A= > re-add tasks which are already on the list.=A0 Ugh.=0A= >=0A= > At the very very least we should tell the user that the kernel goofed=0A= > and that one of their processes won't be getting killed.=0A= =0A= Thanks for the suggestion. As mentioned above I'll mark the kmalloc=0A= allocation error as a failure and can put a log message there.=0A= =0A= >> +=A0=A0=A0=A0 scoped_guard(mutex, &pfn_space_lock) {=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 bool mf_handled =3D false;=0A= >> +=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 /*=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 * Modules registers with MM the= address space mapping to the device memory they=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 * manage. Iterate to identify e= xactly which address space has mapped to this=0A= >> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 * failing PFN.=0A= >=0A= > We're quite lenient about >80 columns nowadays, but overflowing 80 for=0A= > a block comment is rather needless.=0A= =0A= Yes. Since it passed through the strict checkpatch.pl check, I didn't notic= e.=0A= I'll fix it.=