Re: [linux-next:master] [mm] 47325a5c88: WARNING:at_mm/slub.c:#free_large_kmalloc

From: Usama Arif
Date: Wed Jul 10 2024 - 06:35:38 EST



On 10/07/2024 05:51, kernel test robot wrote:
>
>
> Hello,
>
> kernel test robot noticed "WARNING:at_mm/slub.c:#free_large_kmalloc" on:
>
> commit: 47325a5c88c5ee373c973e47c27c7dadcfe88a32 ("mm-store-zero-pages-to-be-swapped-out-in-a-bitmap-v8")
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
>
> [test failed on linux-next/master 82d01fe6ee52086035b201cfa1410a3b04384257]
>
> in testcase: ltp
> version: ltp-x86_64-14c1f76-1_20240706
> with following parameters:
>
> test: commands
>
>
>
> compiler: gcc-13
> test machine: 8 threads 1 sockets Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz (Ivy Bridge) with 16G memory
>
> (please refer to attached dmesg/kmsg for entire log/backtrace)
>
>
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-lkp/202407101031.c6c3c651-lkp@xxxxxxxxx
>
>
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20240710/202407101031.c6c3c651-lkp@xxxxxxxxx
>
>
>
> kern :warn : [ 455.633948] Swap area shorter than signature indicates
> kern :warn : [ 455.634133] ------------[ cut here ]------------
> kern :warn : [ 455.634268] WARNING: CPU: 3 PID: 8129 at mm/slub.c:4538 free_large_kmalloc+0x93/0xe0
> kern :warn : [ 455.635173] Modules linked in: msdos minix vfat fat xfs ext2 netconsole btrfs blake2b_generic xor zstd_compress raid6_pq libcrc32c intel_rapl_msr intel_rapl_common sd_mod x86_pkg_temp_thermal t10_pi intel_powerclamp coretemp crc64_rocksoft_generic crc64_rocksoft crc64 kvm_intel sg ipmi_devintf ipmi_msghandler i915 kvm crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel sha512_ssse3 drm_buddy intel_gtt firewire_ohci rapl mxm_wmi intel_cstate drm_display_helper firewire_core ahci libahci crc_itu_t i2c_i801 intel_uncore ttm libata drm_kms_helper i2c_smbus lpc_ich video wmi binfmt_misc drm loop fuse dm_mod ip_tables
> kern :warn : [ 455.636742] CPU: 3 PID: 8129 Comm: swapon Not tainted 6.10.0-rc6-00357-g47325a5c88c5 #1
> kern :warn : [ 455.636935] Hardware name: /DZ77BH-55K, BIOS BHZ7710H.86A.0097.2012.1228.1346 12/28/2012
> kern :warn : [ 455.637127] RIP: 0010:free_large_kmalloc+0x93/0xe0
> kern :warn : [ 455.637267] Code: 00 41 f7 c4 00 02 00 00 74 01 fb f0 ff 4b 34 74 0b 5b 5d 41 5c 41 5d c3 cc cc cc cc 48 89 df 5b 5d 41 5c 41 5d e9 8d 3f eb ff <0f> 0b 80 3d 14 d8 06 04 00 74 1c 48 89 ef e8 ea b0 1d 02 48 8b 74
> kern :warn : [ 455.637951] RSP: 0018:ffffc9000247fdd8 EFLAGS: 00010246
> kern :warn : [ 455.638098] RAX: 0017ffffc0000000 RBX: ffffea00055cf900 RCX: 0000000000000000
> kern :warn : [ 455.638273] RDX: ffffea0005bb6508 RSI: ffff8881573e4000 RDI: ffffea00055cf900
> kern :warn : [ 455.638505] RBP: ffff8881573e4000 R08: 0000000000000001 R09: fffff5200048ffb5
> kern :warn : [ 455.638679] R10: 0000000000000003 R11: 0000000000000001 R12: ffff8881ee6b2c28
> kern :warn : [ 455.638853] R13: ffff8881393c7890 R14: 00000000ffffffea R15: ffff8881393c7800
> kern :warn : [ 455.639028] FS: 00007fa00e70c840(0000) GS:ffff88833c580000(0000) knlGS:0000000000000000
> kern :warn : [ 455.639218] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> kern :warn : [ 455.639424] CR2: 00005624b13e8000 CR3: 00000003df01e002 CR4: 00000000001706f0
> kern :warn : [ 455.639600] Call Trace:
> kern :warn : [ 455.639695] <TASK>
> kern :warn : [ 455.639787] ? __warn+0xcc/0x260
> kern :warn : [ 455.639900] ? free_large_kmalloc+0x93/0xe0
> kern :warn : [ 455.640025] ? report_bug+0x261/0x2c0
> kern :warn : [ 455.640141] ? handle_bug+0x6d/0x90
> kern :warn : [ 455.640254] ? exc_invalid_op+0x17/0x40
> kern :warn : [ 455.640428] ? asm_exc_invalid_op+0x1a/0x20
> kern :warn : [ 455.640555] ? free_large_kmalloc+0x93/0xe0
> kern :warn : [ 455.640679] __do_sys_swapon+0xaf3/0x1ea0
> kern :warn : [ 455.640806] ? poison_slab_object+0xc5/0x170
> kern :warn : [ 455.640934] ? __pfx___do_sys_swapon+0x10/0x10
> kern :warn : [ 455.641063] ? __x64_sys_close+0x7c/0xd0
> kern :warn : [ 455.641184] ? kmem_cache_free+0xd5/0x3e0
> kern :warn : [ 455.641307] do_syscall_64+0x5f/0x170
> kern :warn : [ 455.641489] entry_SYSCALL_64_after_hwframe+0x76/0x7e
> kern :warn : [ 455.641629] RIP: 0033:0x7fa00e8d7f97
> kern :warn : [ 455.641746] Code: 73 01 c3 48 8b 0d 69 2e 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a7 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 39 2e 0d 00 f7 d8 64 89 01 48
> kern :warn : [ 455.642117] RSP: 002b:00007ffc063cb6e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a7
> kern :warn : [ 455.642302] RAX: ffffffffffffffda RBX: 00005624b13d89a0 RCX: 00007fa00e8d7f97
> kern :warn : [ 455.642535] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005624b13d89a0
> kern :warn : [ 455.642709] RBP: 0000000000000000 R08: 0000000000000ff6 R09: 0000000000001000
> kern :warn : [ 455.642882] R10: 4e45505355533253 R11: 0000000000000246 R12: 00007ffc063cb91c
> kern :warn : [ 455.643056] R13: 00000000ffffffff R14: 0000000012c00000 R15: 00005624b13d95d0
> kern :warn : [ 455.643231] </TASK>
> kern :warn : [ 455.643321] ---[ end trace 0000000000000000 ]---
> kern :warn : [ 455.643507] object pointer: 0x000000003fde23f4
> kern :err : [ 455.643635] ==================================================================
> kern :err : [ 455.643807] BUG: KASAN: double-free in __do_sys_swapon+0xaf3/0x1ea0
> kern :err : [ 455.643978] Free of addr ffff8881573e4000 by task swapon/8129
>
> kern :err : [ 455.644198] CPU: 3 PID: 8129 Comm: swapon Tainted: G W 6.10.0-rc6-00357-g47325a5c88c5 #1
> kern :err : [ 455.644406] Hardware name: /DZ77BH-55K, BIOS BHZ7710H.86A.0097.2012.1228.1346 12/28/2012
> kern :err : [ 455.644590] Call Trace:
> kern :err : [ 455.644681] <TASK>
> kern :err : [ 455.644768] dump_stack_lvl+0x53/0x70
> kern :err : [ 455.644883] print_address_description+0x30/0x410
> kern :err : [ 455.645033] ? __do_sys_swapon+0xaf3/0x1ea0
> kern :err : [ 455.645158] print_report+0xb9/0x2b0
> kern :err : [ 455.645275] ? __do_sys_swapon+0xaf3/0x1ea0
> kern :err : [ 455.645397] ? kasan_addr_to_slab+0xd/0xb0
> kern :err : [ 455.645516] ? __do_sys_swapon+0xaf3/0x1ea0
> kern :err : [ 455.645639] kasan_report_invalid_free+0x94/0xc0
> kern :err : [ 455.645769] ? __do_sys_swapon+0xaf3/0x1ea0
> kern :err : [ 455.645891] free_large_kmalloc+0xb8/0xe0
> kern :err : [ 455.646010] __do_sys_swapon+0xaf3/0x1ea0
> kern :err : [ 455.646130] ? poison_slab_object+0xc5/0x170
> kern :err : [ 455.646254] ? __pfx___do_sys_swapon+0x10/0x10
> kern :err : [ 455.646379] ? __x64_sys_close+0x7c/0xd0
> kern :err : [ 455.646498] ? kmem_cache_free+0xd5/0x3e0
> kern :err : [ 455.646619] do_syscall_64+0x5f/0x170
> kern :err : [ 455.646735] entry_SYSCALL_64_after_hwframe+0x76/0x7e
> kern :err : [ 455.646871] RIP: 0033:0x7fa00e8d7f97
> kern :err : [ 455.646985] Code: 73 01 c3 48 8b 0d 69 2e 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a7 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 39 2e 0d 00 f7 d8 64 89 01 48
> kern :err : [ 455.647343] RSP: 002b:00007ffc063cb6e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a7
> kern :err : [ 455.647521] RAX: ffffffffffffffda RBX: 00005624b13d89a0 RCX: 00007fa00e8d7f97
> kern :err : [ 455.647692] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005624b13d89a0
> kern :err : [ 455.647863] RBP: 0000000000000000 R08: 0000000000000ff6 R09: 0000000000001000
> kern :err : [ 455.648036] R10: 4e45505355533253 R11: 0000000000000246 R12: 00007ffc063cb91c
> kern :err : [ 455.648208] R13: 00000000ffffffff R14: 0000000012c00000 R15: 00005624b13d95d0
> kern :err : [ 455.648387] </TASK>
>
> kern :err : [ 455.648549] The buggy address belongs to the physical page:
> kern :warn : [ 455.648692] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881573e5b30 pfn:0x1573e4
> kern :warn : [ 455.648902] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
> kern :warn : [ 455.649065] raw: 0017ffffc0000000 ffffea0005bb6508 ffff88833c7cb600 0000000000000000
> kern :warn : [ 455.649249] raw: ffff8881573e5b30 0000000000000000 00000000ffffffff 0000000000000000
> kern :warn : [ 455.649430] page dumped because: kasan: bad access detected
>
> kern :err : [ 455.649647] Memory state around the buggy address:
> kern :err : [ 455.649777] ffff8881573e3f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> kern :err : [ 455.649945] ffff8881573e3f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> kern :err : [ 455.650115] >ffff8881573e4000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> kern :err : [ 455.650286] ^
> kern :err : [ 455.650392] ffff8881573e4080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> kern :err : [ 455.650563] ffff8881573e4100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> kern :err : [ 455.650733] ==================================================================
> kern :warn : [ 455.650954] Disabling lock debugging due to kernel taint
> user :notice: [ 455.655806] mkswap01 3 TINFO: Can not do swapon on /dev/loop0.
>
>
>


I believe the below diff should solve the warning and double-free. Could this be folded into the patch?


commit 5c9ec83f36ba85425132fba38731d524202b8aab (HEAD)
Author: Usama Arif <usamaarif642@xxxxxxxxx>
Date: Wed Jul 10 11:21:56 2024 +0100

mm: initialize zeromap to NULL at swapon

If swapon fails before zeromap is initialized, kvfree should operate
on a NULL pointer.

Signed-off-by: Usama Arif <usamaarif642@xxxxxxxxx>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index e263511dbb6e..63792ac867c7 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3105,6 +3105,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
struct page *page = NULL;
struct inode *inode = NULL;
bool inced_nr_rotate_swap = false;
+ unsigned long *zeromap = NULL;

if (swap_flags & ~SWAP_FLAGS_VALID)
return -EINVAL;
@@ -3184,12 +3185,13 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
* Use kvmalloc_array instead of bitmap_zalloc as the allocation order might
* be above MAX_PAGE_ORDER incase of a large swap file.
*/
- p->zeromap = kvmalloc_array(BITS_TO_LONGS(maxpages), sizeof(long),
- GFP_KERNEL | __GFP_ZERO);
- if (!p->zeromap) {
+ zeromap = kvmalloc_array(BITS_TO_LONGS(maxpages), sizeof(long),
+ GFP_KERNEL | __GFP_ZERO);
+ if (!zeromap) {
error = -ENOMEM;
goto bad_swap_unlock_inode;
}
+ p->zeromap = zeromap;

if (p->bdev && bdev_stable_writes(p->bdev))
p->flags |= SWP_STABLE_WRITES;
@@ -3345,7 +3347,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
p->flags = 0;
spin_unlock(&swap_lock);
vfree(swap_map);
- kvfree(p->zeromap);
+ kvfree(zeromap);
kvfree(cluster_info);
if (inced_nr_rotate_swap)
atomic_dec(&nr_rotate_swap);