----- On Mar 28, 2018, at 10:06 AM, Mathieu Desnoyers [email protected] wrote:
> ----- On Mar 28, 2018, at 2:47 AM, Boqun Feng [email protected] wrote: > >> On Tue, Mar 27, 2018 at 12:05:23PM -0400, Mathieu Desnoyers wrote: >> [...] >>> Changes since v11: >>> >>> - Replace task struct rseq_preempt, rseq_signal, and rseq_migrate >>> bool by u32 rseq_event_mask. >> [...] >>> @@ -979,6 +980,17 @@ struct task_struct { >>> unsigned long numa_pages_migrated; >>> #endif /* CONFIG_NUMA_BALANCING */ >>> >>> +#ifdef CONFIG_RSEQ >>> + struct rseq __user *rseq; >>> + u32 rseq_len; >>> + u32 rseq_sig; >>> + /* >>> + * RmW on rseq_event_mask must be performed atomically >>> + * with respect to preemption. >>> + */ >>> + unsigned long rseq_event_mask; >> >> s/unsigned long/u32 > > good point, fixed. > Actually, by having a u32 instead of unsigned long here, it triggers those warnings: In file included from ./include/linux/bitops.h:38:0, from ./include/linux/kernel.h:11, from certs/system_keyring.c:13: ./arch/x86/include/asm/bitops.h:73:1: note: expected ‘volatile long unsigned int *’ but argument is of type ‘u32 *’ set_bit(long nr, volatile unsigned long *addr) ^ I suspect that casting the u32 * to a unsigned long * is not a safe approach, because the code can generate a load/store on unallocated memory (kasan might complain). Thoughts ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
