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bh=VYxb6YVvzNpAaHF/Ne/1jHyX0VThAeorFjx+TwB2vso=; b=rmxThhLl+S4cREfq6DEuHysowvcvWNOgl0nlA0FwJPR+LtMO5AFNVZquVYsPXku88eAuax TXHMNOGkjR7wYdJlIQU/AZ/HZ+Ss+UZZJOpExB5UIm+hL/G4E0yS9cJWrDp8R+KjkywNnA 1SOqcdIQ3WZYFqu7OPGpEawfD9PO/oU= X-Rspam-User: X-Stat-Signature: ogwzt9bmtrucxi6i4saozpt5486ehkmh X-Rspamd-Queue-Id: 1953412005A Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2022-7-12 header.b=N2SrrFNf; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=G4KPEMsP; spf=pass (imf29.hostedemail.com: domain of dan.carpenter@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=dan.carpenter@oracle.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); dmarc=pass (policy=none) header.from=oracle.com X-Rspamd-Server: rspam07 X-HE-Tag: 1661842946-571996 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: On Tue, Aug 30, 2022 at 08:46:58AM +0200, Michal Hocko wrote: > On Tue 30-08-22 09:30:26, Dan Carpenter wrote: > > Hello Michal Hocko, > > > > The patch e8fedfea3dea: "mm: reduce noise in show_mem for lowmem > > allocations" from Aug 23, 2022, leads to the following Smatch static > > checker warning: > > > > kernel/panic.c:190 panic_print_sys_info() > > warn: sleeping in atomic context > > What is this warning saying? > This is a Smatch warning. > > 189 if (panic_print & PANIC_PRINT_MEM_INFO) > > --> 190 show_mem(0, NULL, GFP_HIGHUSER_MOVABLE); > > ^^^^^^^^^^^^^^^^^^^^ > > This obviously seems very deliberate and a lot of weird stuff happens > > during panic(). But the panic() function disables preemption so > > shouldn't this be GFP_ATOMIC? GFP_HIGHUSER_MOVABLE has __GFP_RECLAIM > > and triggering swap during a panic seems bad. > > This function shouldn't ever be allocating any memory. The flag is > solely to infer which memory zones should be displayed. It acts as a > filter. Is it possible that the checker misinterprets the parameter's > meaning? Ah. Yes. Smatch sees every gfp_t as a sleep/no sleep marker. I didn't realize it wasn't used like that here. Thanks! regards, dan carpenter