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Howlett" , Lorenzo Stoakes , Alex Deucher , =?ISO-8859-15?Q?Christian_K=F6nig?= , Andrew Morton , David Hildenbrand , amd-gfx@lists.freedesktop.org, linux-mm@kvack.org, Vlastimil Babka , Jann Horn , Pedro Falcato Subject: Re: [PATCH v3 2/3] mm: only interrupt taking all mm locks on fatal signal In-Reply-To: Message-ID: <5dfbf2f9-0948-cd59-5c59-a6ee946ff9f2@redhat.com> References: <7whbqlfrwjr4z2d4bpny3rjyl5tetdyx7ccf52uvby7hgywoym@6l6m2xcytez7> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: OfByKVq9WaLWftpSg42AJSc_GUPvzRYrJhajrHE0sEc_1767703957 X-Mimecast-Originator: redhat.com Content-Type: multipart/mixed; BOUNDARY="-1463811712-1739719334-1767702910=:329667" Content-ID: <4dd8c681-f09b-0e56-d450-138c4d923bc8@redhat.com> X-Stat-Signature: 34ne3j5pzac1n4dfj9cetkc1ytdims9p X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 45ABF100006 X-Rspam-User: X-HE-Tag: 1767703963-115480 X-HE-Meta: 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 d65zrz/H fy/mj0itunQu7F83dCfjKMbZsnAsUKlHAuNViK1W3FG+qvCr+WKfJw4GkjKRqUIS0Y9OwbwJSGluPP+qPRXSbiMPEfDFVHNANxDYkeLBI0Cakns3aG4CRReaUeiJPLX04RJ6dcAGjRYjfo7xFwY+FO+2mchgsY8PVm8TQvt8njUFSyL6AdlMR4UoXfTZOG47Lb5V0x50urxAdItU9aIjRCILuSK4yD8ktzdBlNlUbHGPUkmQ3NZk25Kg2IlZ6umyrk9glZTpGEV24x1jh6wRpnSCWGm8QMnqS23aziVksVIY1AEjgNootPkpjXm2Iav8lUqBGgtSwnY1RdqO0Y8wYf0tl2fzAbP5DeE7iSRJKjBndTSMPupVvbn3zGJBZxH6tdwxmn0TnwNtQRoZsRaKormnIji2h8826LL0xVMWmDsmP4Xjd0yKdl6NcrPl0I1STpafd7TBerdE4kbksQxS/yP3p71Z9Xtgua9RY94Jy2R1Xjxg= 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: This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. ---1463811712-1739719334-1767702910=:329667 Content-Type: text/plain; CHARSET=ISO-8859-15 Content-Transfer-Encoding: 8BIT Content-ID: <0b5eb857-a42d-63b4-aa09-99752d29977a@redhat.com> On Tue, 6 Jan 2026, Michel Dänzer wrote: > On 1/5/26 19:15, Liam R. Howlett wrote: > > * Mikulas Patocka [260104 16:17]: > > > > I'm not saying it's wrong to change the signal handling, but this is > > very much working around a bug in userspace constantly hammering a task > > with signals and then is surprised there is a response that the kernel > > was interrupted. > > I'd go further than that. If user space fails to retry the system call > in response to -EINTR, that's a user-space bug, period. It can happen > anytime for any number of other reasons. (That most system calls happen > to get away without it most of the time doesn't make it not a bug) So, I tried this - just for fun - and the machine doesn't even boot. I get a lot of errors about inability to open particular files on the console. Userspace is buggy, according to your definition, regardless of whether you like it or not. Mikulas --- fs/open.c | 3 +++ 1 file changed, 3 insertions(+) Index: linux-2.6/fs/open.c =================================================================== --- linux-2.6.orig/fs/open.c 2025-12-31 20:10:31.000000000 +0100 +++ linux-2.6/fs/open.c 2026-01-06 13:28:01.000000000 +0100 @@ -1419,6 +1419,9 @@ static int do_sys_openat2(int dfd, const struct filename *tmp __free(putname) = NULL; int err; + if (current->pid != 1 && !(get_random_u8() & 0x1)) + return -EINTR; + err = build_open_flags(how, &op); if (unlikely(err)) return err; ---1463811712-1739719334-1767702910=:329667--