On 02/16/2015 05:47 PM, Dmitry Vyukov wrote: > Can a module be freed in an interrupt? > > Since commit: c749637909ee ("module: fix race in kallsyms resolution during module load success.") module's init section always freed rcu callback (rcu callbacks executed from softirq) Currently, with DEBUG_PAGEALLOC and KASAN module loading always causing kernel crash. It's harder to trigger this without DEBUG_PAGEALLOC because of lazy tlb flushing in vmalloc. BUG: unable to handle kernel paging request at fffffbfff4011000 IP: [<ffffffff811d8f7b>] __asan_load8+0x2b/0xa0 PGD 7ffa3063 PUD 7ffa2063 PMD 484ea067 PTE 0 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: ipv6 CPU: 0 PID: 30 Comm: kworker/0:1 Tainted: G W 3.19.0-rc7-next-20150209+ #209 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 Workqueue: events free_work task: ffff88006c5a8870 ti: ffff88006c630000 task.ti: ffff88006c630000 RIP: 0010:[<ffffffff811d8f7b>] [<ffffffff811d8f7b>] __asan_load8+0x2b/0xa0 RSP: 0018:ffff88006c637cd8 EFLAGS: 00010286 RAX: fffffbfff4011000 RBX: ffffffffa0088000 RCX: ffffed000da000a9 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffffffffa0088000 RBP: ffff88006c637d08 R08: 0000000000000000 R09: ffff88006d007840 R10: ffff88006d000540 R11: ffffed000da000a9 R12: ffffffffa0088000 R13: ffff88006d61a5d8 R14: ffff88006d61a5d8 R15: ffff88006d61a5c0 FS: 0000000000000000(0000) GS:ffff88006d600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: fffffbfff4011000 CR3: 000000004d967000 CR4: 00000000000006b0 Stack: ffff88006c637ce8 fffffbfff4011000 ffffffffa0088000 ffff88006d61a5d8 ffff88006d61a5d8 ffff88006d61a5c0 ffff88006c637d28 ffffffff811bb1b8 ffff88006c5bc618 ffff88006d617b28 ffff88006c637db8 ffffffff8108e1b0 Call Trace: [<ffffffff811bb1b8>] free_work+0x38/0x60 [<ffffffff8108e1b0>] process_one_work+0x2a0/0x7d0 [<ffffffff8108f653>] worker_thread+0x93/0x840 [<ffffffff8108f5c0>] ? init_pwq.part.11+0x10/0x10 [<ffffffff81096f37>] kthread+0x177/0x1a0 [<ffffffff81096dc0>] ? kthread_worker_fn+0x290/0x290 [<ffffffff81096dc0>] ? kthread_worker_fn+0x290/0x290 [<ffffffff8158cd7c>] ret_from_fork+0x7c/0xb0 [<ffffffff81096dc0>] ? kthread_worker_fn+0x290/0x290 Code: 48 b8 ff ff ff ff ff 7f ff ff 55 48 89 e5 48 83 ec 30 48 39 c7 76 59 48 ba 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 48 01 d0 <66> 83 38 00 75 07 c9 c3 0f 1f 44 00 00 48 8d 4f 07 48 89 ce 48 RIP [<ffffffff811d8f7b>] __asan_load8+0x2b/0xa0 RSP <ffff88006c637cd8> CR2: fffffbfff4011000 ---[ end trace b9411d841784b6cf ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html