forked from Minki/linux
lib: add tests for reference tracker
This module uses reference tracker, forcing two issues. 1) Double free of a tracker 2) leak of two trackers, one being allocated from softirq context. "modprobe test_ref_tracker" would emit the following traces. (Use scripts/decode_stacktrace.sh if necessary) [ 171.648681] reference already released. [ 171.653213] allocated in: [ 171.656523] alloctest_ref_tracker_alloc2+0x1c/0x20 [test_ref_tracker] [ 171.656526] init_module+0x86/0x1000 [test_ref_tracker] [ 171.656528] do_one_initcall+0x9c/0x220 [ 171.656532] do_init_module+0x60/0x240 [ 171.656536] load_module+0x32b5/0x3610 [ 171.656538] __do_sys_init_module+0x148/0x1a0 [ 171.656540] __x64_sys_init_module+0x1d/0x20 [ 171.656542] do_syscall_64+0x4a/0xb0 [ 171.656546] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 171.656549] freed in: [ 171.659520] alloctest_ref_tracker_free+0x13/0x20 [test_ref_tracker] [ 171.659522] init_module+0xec/0x1000 [test_ref_tracker] [ 171.659523] do_one_initcall+0x9c/0x220 [ 171.659525] do_init_module+0x60/0x240 [ 171.659527] load_module+0x32b5/0x3610 [ 171.659529] __do_sys_init_module+0x148/0x1a0 [ 171.659532] __x64_sys_init_module+0x1d/0x20 [ 171.659534] do_syscall_64+0x4a/0xb0 [ 171.659536] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 171.659575] ------------[ cut here ]------------ [ 171.659576] WARNING: CPU: 5 PID: 13016 at lib/ref_tracker.c:112 ref_tracker_free+0x224/0x270 [ 171.659581] Modules linked in: test_ref_tracker(+) [ 171.659591] CPU: 5 PID: 13016 Comm: modprobe Tainted: G S 5.16.0-smp-DEV #290 [ 171.659595] RIP: 0010:ref_tracker_free+0x224/0x270 [ 171.659599] Code: 5e 41 5f 5d c3 48 c7 c7 04 9c 74 a6 31 c0 e8 62 ee 67 00 83 7b 14 00 75 1a 83 7b 18 00 75 30 4c 89 ff 4c 89 f6 e8 9c 00 69 00 <0f> 0b bb ea ff ff ff eb ae 48 c7 c7 3a 0a 77 a6 31 c0 e8 34 ee 67 [ 171.659601] RSP: 0018:ffff89058ba0bbd0 EFLAGS: 00010286 [ 171.659603] RAX: 0000000000000029 RBX: ffff890586b19780 RCX: 08895bff57c7d100 [ 171.659604] RDX: c0000000ffff7fff RSI: 0000000000000282 RDI: ffffffffc0407000 [ 171.659606] RBP: ffff89058ba0bc88 R08: 0000000000000000 R09: ffffffffa6f342e0 [ 171.659607] R10: 00000000ffff7fff R11: 0000000000000000 R12: 000000008f000000 [ 171.659608] R13: 0000000000000014 R14: 0000000000000282 R15: ffffffffc0407000 [ 171.659609] FS: 00007f97ea29d740(0000) GS:ffff8923ff940000(0000) knlGS:0000000000000000 [ 171.659611] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 171.659613] CR2: 00007f97ea299000 CR3: 0000000186b4a004 CR4: 00000000001706e0 [ 171.659614] Call Trace: [ 171.659615] <TASK> [ 171.659631] ? alloctest_ref_tracker_free+0x13/0x20 [test_ref_tracker] [ 171.659633] ? init_module+0x105/0x1000 [test_ref_tracker] [ 171.659636] ? do_one_initcall+0x9c/0x220 [ 171.659638] ? do_init_module+0x60/0x240 [ 171.659641] ? load_module+0x32b5/0x3610 [ 171.659644] ? __do_sys_init_module+0x148/0x1a0 [ 171.659646] ? __x64_sys_init_module+0x1d/0x20 [ 171.659649] ? do_syscall_64+0x4a/0xb0 [ 171.659652] ? entry_SYSCALL_64_after_hwframe+0x44/0xae [ 171.659656] ? 0xffffffffc040a000 [ 171.659658] alloctest_ref_tracker_free+0x13/0x20 [test_ref_tracker] [ 171.659660] init_module+0x105/0x1000 [test_ref_tracker] [ 171.659663] do_one_initcall+0x9c/0x220 [ 171.659666] do_init_module+0x60/0x240 [ 171.659669] load_module+0x32b5/0x3610 [ 171.659672] __do_sys_init_module+0x148/0x1a0 [ 171.659676] __x64_sys_init_module+0x1d/0x20 [ 171.659678] do_syscall_64+0x4a/0xb0 [ 171.659694] ? exc_page_fault+0x6e/0x140 [ 171.659696] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 171.659698] RIP: 0033:0x7f97ea3dbe7a [ 171.659700] Code: 48 8b 0d 61 8d 06 00 f7 d8 64 89 01 48 83 c8 ff c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 49 89 ca b8 af 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2e 8d 06 00 f7 d8 64 89 01 48 [ 171.659701] RSP: 002b:00007ffea67ce608 EFLAGS: 00000246 ORIG_RAX: 00000000000000af [ 171.659703] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f97ea3dbe7a [ 171.659704] RDX: 00000000013a0ba0 RSI: 0000000000002808 RDI: 00007f97ea299000 [ 171.659705] RBP: 00007ffea67ce670 R08: 0000000000000003 R09: 0000000000000000 [ 171.659706] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000013a1048 [ 171.659707] R13: 00000000013a0ba0 R14: 0000000001399930 R15: 00000000013a1030 [ 171.659709] </TASK> [ 171.659710] ---[ end trace f5dbd6afa41e60a9 ]--- [ 171.659712] leaked reference. [ 171.663393] alloctest_ref_tracker_alloc0+0x1c/0x20 [test_ref_tracker] [ 171.663395] test_ref_tracker_timer_func+0x9/0x20 [test_ref_tracker] [ 171.663397] call_timer_fn+0x31/0x140 [ 171.663401] expire_timers+0x46/0x110 [ 171.663403] __run_timers+0x16f/0x1b0 [ 171.663404] run_timer_softirq+0x1d/0x40 [ 171.663406] __do_softirq+0x148/0x2d3 [ 171.663408] leaked reference. [ 171.667101] alloctest_ref_tracker_alloc1+0x1c/0x20 [test_ref_tracker] [ 171.667103] init_module+0x81/0x1000 [test_ref_tracker] [ 171.667104] do_one_initcall+0x9c/0x220 [ 171.667106] do_init_module+0x60/0x240 [ 171.667108] load_module+0x32b5/0x3610 [ 171.667111] __do_sys_init_module+0x148/0x1a0 [ 171.667113] __x64_sys_init_module+0x1d/0x20 [ 171.667115] do_syscall_64+0x4a/0xb0 [ 171.667117] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 171.667131] ------------[ cut here ]------------ [ 171.667132] WARNING: CPU: 5 PID: 13016 at lib/ref_tracker.c:30 ref_tracker_dir_exit+0x104/0x130 [ 171.667136] Modules linked in: test_ref_tracker(+) [ 171.667144] CPU: 5 PID: 13016 Comm: modprobe Tainted: G S W 5.16.0-smp-DEV #290 [ 171.667147] RIP: 0010:ref_tracker_dir_exit+0x104/0x130 [ 171.667150] Code: 01 00 00 00 00 ad de 48 89 03 4c 89 63 08 48 89 df e8 20 a0 d5 ff 4c 89 f3 4d 39 ee 75 a8 4c 89 ff 48 8b 75 d0 e8 7c 05 69 00 <0f> 0b eb 0c 4c 89 ff 48 8b 75 d0 e8 6c 05 69 00 41 8b 47 08 83 f8 [ 171.667151] RSP: 0018:ffff89058ba0bc68 EFLAGS: 00010286 [ 171.667154] RAX: 08895bff57c7d100 RBX: ffffffffc0407010 RCX: 000000000000003b [ 171.667156] RDX: 000000000000003c RSI: 0000000000000282 RDI: ffffffffc0407000 [ 171.667157] RBP: ffff89058ba0bc98 R08: 0000000000000000 R09: ffffffffa6f342e0 [ 171.667159] R10: 00000000ffff7fff R11: 0000000000000000 R12: dead000000000122 [ 171.667160] R13: ffffffffc0407010 R14: ffffffffc0407010 R15: ffffffffc0407000 [ 171.667162] FS: 00007f97ea29d740(0000) GS:ffff8923ff940000(0000) knlGS:0000000000000000 [ 171.667164] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 171.667166] CR2: 00007f97ea299000 CR3: 0000000186b4a004 CR4: 00000000001706e0 [ 171.667169] Call Trace: [ 171.667170] <TASK> [ 171.667171] ? 0xffffffffc040a000 [ 171.667173] init_module+0x126/0x1000 [test_ref_tracker] [ 171.667175] do_one_initcall+0x9c/0x220 [ 171.667179] do_init_module+0x60/0x240 [ 171.667182] load_module+0x32b5/0x3610 [ 171.667186] __do_sys_init_module+0x148/0x1a0 [ 171.667189] __x64_sys_init_module+0x1d/0x20 [ 171.667192] do_syscall_64+0x4a/0xb0 [ 171.667194] ? exc_page_fault+0x6e/0x140 [ 171.667196] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 171.667199] RIP: 0033:0x7f97ea3dbe7a [ 171.667200] Code: 48 8b 0d 61 8d 06 00 f7 d8 64 89 01 48 83 c8 ff c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 49 89 ca b8 af 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2e 8d 06 00 f7 d8 64 89 01 48 [ 171.667201] RSP: 002b:00007ffea67ce608 EFLAGS: 00000246 ORIG_RAX: 00000000000000af [ 171.667203] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f97ea3dbe7a [ 171.667204] RDX: 00000000013a0ba0 RSI: 0000000000002808 RDI: 00007f97ea299000 [ 171.667205] RBP: 00007ffea67ce670 R08: 0000000000000003 R09: 0000000000000000 [ 171.667206] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000013a1048 [ 171.667207] R13: 00000000013a0ba0 R14: 0000000001399930 R15: 00000000013a1030 [ 171.667209] </TASK> [ 171.667210] ---[ end trace f5dbd6afa41e60aa ]--- Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet
Jakub Kicinski
parent
4e66934eaa
commit
914a7b5000
@ -2106,6 +2106,16 @@ config BACKTRACE_SELF_TEST
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Say N if you are unsure.
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config TEST_REF_TRACKER
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tristate "Self test for reference tracker"
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depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
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select REF_TRACKER
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help
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This option provides a kernel module performing tests
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using reference tracker infrastructure.
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Say N if you are unsure.
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config RBTREE_TEST
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tristate "Red-Black tree test"
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depends on DEBUG_KERNEL
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@ -101,7 +101,7 @@ obj-$(CONFIG_TEST_LOCKUP) += test_lockup.o
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obj-$(CONFIG_TEST_HMM) += test_hmm.o
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obj-$(CONFIG_TEST_FREE_PAGES) += test_free_pages.o
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obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
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obj-$(CONFIG_TEST_REF_TRACKER) += test_ref_tracker.o
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#
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# CFLAGS for compiling floating point code inside the kernel. x86/Makefile turns
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# off the generation of FPU/SSE* instructions for kernel proper but FPU_FLAGS
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115
lib/test_ref_tracker.c
Normal file
115
lib/test_ref_tracker.c
Normal file
@ -0,0 +1,115 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Referrence tracker self test.
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*
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* Copyright (c) 2021 Eric Dumazet <edumazet@google.com>
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/ref_tracker.h>
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#include <linux/slab.h>
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#include <linux/timer.h>
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static struct ref_tracker_dir ref_dir;
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static struct ref_tracker *tracker[20];
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#define TRT_ALLOC(X) static noinline void \
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alloctest_ref_tracker_alloc##X(struct ref_tracker_dir *dir, \
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struct ref_tracker **trackerp) \
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{ \
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ref_tracker_alloc(dir, trackerp, GFP_KERNEL); \
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}
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TRT_ALLOC(1)
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TRT_ALLOC(2)
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TRT_ALLOC(3)
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TRT_ALLOC(4)
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TRT_ALLOC(5)
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TRT_ALLOC(6)
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TRT_ALLOC(7)
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TRT_ALLOC(8)
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TRT_ALLOC(9)
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TRT_ALLOC(10)
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TRT_ALLOC(11)
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TRT_ALLOC(12)
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TRT_ALLOC(13)
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TRT_ALLOC(14)
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TRT_ALLOC(15)
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TRT_ALLOC(16)
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TRT_ALLOC(17)
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TRT_ALLOC(18)
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TRT_ALLOC(19)
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#undef TRT_ALLOC
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static noinline void
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alloctest_ref_tracker_free(struct ref_tracker_dir *dir,
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struct ref_tracker **trackerp)
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{
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ref_tracker_free(dir, trackerp);
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}
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static struct timer_list test_ref_tracker_timer;
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static atomic_t test_ref_timer_done = ATOMIC_INIT(0);
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static void test_ref_tracker_timer_func(struct timer_list *t)
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{
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ref_tracker_alloc(&ref_dir, &tracker[0], GFP_ATOMIC);
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atomic_set(&test_ref_timer_done, 1);
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}
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static int __init test_ref_tracker_init(void)
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{
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int i;
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ref_tracker_dir_init(&ref_dir, 100);
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timer_setup(&test_ref_tracker_timer, test_ref_tracker_timer_func, 0);
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mod_timer(&test_ref_tracker_timer, jiffies + 1);
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alloctest_ref_tracker_alloc1(&ref_dir, &tracker[1]);
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alloctest_ref_tracker_alloc2(&ref_dir, &tracker[2]);
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alloctest_ref_tracker_alloc3(&ref_dir, &tracker[3]);
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alloctest_ref_tracker_alloc4(&ref_dir, &tracker[4]);
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alloctest_ref_tracker_alloc5(&ref_dir, &tracker[5]);
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alloctest_ref_tracker_alloc6(&ref_dir, &tracker[6]);
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alloctest_ref_tracker_alloc7(&ref_dir, &tracker[7]);
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alloctest_ref_tracker_alloc8(&ref_dir, &tracker[8]);
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alloctest_ref_tracker_alloc9(&ref_dir, &tracker[9]);
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alloctest_ref_tracker_alloc10(&ref_dir, &tracker[10]);
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alloctest_ref_tracker_alloc11(&ref_dir, &tracker[11]);
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alloctest_ref_tracker_alloc12(&ref_dir, &tracker[12]);
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alloctest_ref_tracker_alloc13(&ref_dir, &tracker[13]);
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alloctest_ref_tracker_alloc14(&ref_dir, &tracker[14]);
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alloctest_ref_tracker_alloc15(&ref_dir, &tracker[15]);
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alloctest_ref_tracker_alloc16(&ref_dir, &tracker[16]);
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alloctest_ref_tracker_alloc17(&ref_dir, &tracker[17]);
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alloctest_ref_tracker_alloc18(&ref_dir, &tracker[18]);
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alloctest_ref_tracker_alloc19(&ref_dir, &tracker[19]);
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/* free all trackers but first 0 and 1. */
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for (i = 2; i < ARRAY_SIZE(tracker); i++)
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alloctest_ref_tracker_free(&ref_dir, &tracker[i]);
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/* Attempt to free an already freed tracker. */
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alloctest_ref_tracker_free(&ref_dir, &tracker[2]);
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while (!atomic_read(&test_ref_timer_done))
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msleep(1);
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/* This should warn about tracker[0] & tracker[1] being not freed. */
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ref_tracker_dir_exit(&ref_dir);
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return 0;
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}
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static void __exit test_ref_tracker_exit(void)
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{
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}
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module_init(test_ref_tracker_init);
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module_exit(test_ref_tracker_exit);
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MODULE_LICENSE("GPL v2");
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