lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 29 Jan 2016 15:54:07 +0900 From: Byungchul Park <byungchul.park@....com> To: Sergey Senozhatsky <sergey.senozhatsky.work@...il.com> Cc: Peter Hurley <peter@...leysoftware.com>, Sergey Senozhatsky <sergey.senozhatsky@...il.com>, akpm@...ux-foundation.org, mingo@...nel.org, linux-kernel@...r.kernel.org, akinobu.mita@...il.com, jack@...e.cz, torvalds@...ux-foundation.org Subject: Re: [PATCH v4] lib/spinlock_debug.c: prevent a recursive cycle in the debug code On Fri, Jan 29, 2016 at 09:27:03AM +0900, Sergey Senozhatsky wrote: > > well, the stack is surely limited, but on every > spin_dump()->spin_lock() recursive call it does another > round of > > u64 loops = loops_per_jiffy * HZ; > > for (i = 0; i < loops; i++) { > if (arch_spin_trylock(&lock->raw_lock)) > return; > __delay(1); > } > > so if you have 1000 spin_dump()->spin_lock() then, well, > something has been holding the lock for '1000 * loops_per_jiffy * HZ'. Or the printk() is heavily called and the lock is congested.
Powered by blists - more mailing lists