The fix commit [1] is in Oracular 6.11.
[1] bcache: fix variable length array abuse in btree_iter
** Changed in: linux (Ubuntu Oracular)
Status: Triaged => Fix Released
** Changed in: linux (Ubuntu)
Status: Triaged => Fix Released
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https://bugs.launchpad.net/bugs/2039368
Title:
UBSAN: array-index-out-of-bounds in
/build/linux-D15vQj/linux-6.5.0/drivers/md/bcache/bset.c:1098:3
Status in linux package in Ubuntu:
Fix Released
Status in linux source package in Jammy:
Invalid
Status in linux source package in Mantic:
Won't Fix
Status in linux source package in Noble:
Fix Released
Status in linux source package in Oracular:
Fix Released
Bug description:
[Impact]
Currently there are UBSAN warnings that show up when running bcache on
jammy HWE, Mantic and noble. For now no side effects have been
observed but such an issue could potentially cause a crash or corrupt
data.
[Fix]
There is currently a fix upstream provided by the following patch:
* 3a861560ccb3 "bcache: fix variable length array abuse in btree_iter"
[Test Case]
1. Setup bcache on a jammy HWE kernel or mantic or noble machine. This can be
done following the steps in this wiki: https://wiki.ubuntu.com/ServerTeam/Bcache
2. Restart the machine
3. After restarting the machine, the following UBSAN warnings and call traces
can be seen in dmesg:
[ 3.824281] UBSAN: array-index-out-of-bounds in
/build/linux-hwe-6.5-QmAt2N/linux-hwe-6.5-6.5.0/drivers/md/bcache/bset.c:1098:3
[ 3.826338] index 4 is out of range for type 'btree_iter_set [4]'
[ 3.826812] CPU: 13 PID: 184 Comm: kworker/13:1 Not tainted
6.5.0-41-generic #41~22.04.2-Ubuntu
[ 3.827817] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
[ 3.828835] Workqueue: events register_cache_worker [bcache]
[ 3.829429] Call Trace:
[ 3.830626] <TASK>
[ 3.831638] dump_stack_lvl+0x48/0x70
[ 3.832227] dump_stack+0x10/0x20
[ 3.832785] __ubsan_handle_out_of_bounds+0xc6/0x110
[ 3.833357] bch_btree_iter_push+0x4e6/0x4f0 [bcache]
[ 3.834052] bch_btree_node_read_done+0xfc/0x450 [bcache]
[ 3.834653] ? mempool_kfree+0xe/0x20
[ 3.835211] bch_btree_node_read+0xf8/0x1e0 [bcache]
[ 3.835832] ? __pfx_closure_sync_fn+0x10/0x10 [bcache]
[ 3.836474] bch_btree_node_get.part.0+0x160/0x340 [bcache]
[ 3.837161] ? __bch_btree_ptr_invalid+0x60/0xd0 [bcache]
[ 3.837838] ? __pfx_up_write+0x10/0x10
[ 3.838739] bch_btree_node_get+0x16/0x30 [bcache]
[ 3.844949] </TASK>
[ 4.029242] UBSAN: array-index-out-of-bounds in
/build/linux-hwe-6.5-QmAt2N/linux-hwe-6.5-6.5.0/drivers/md/bcache/bset.c:1207:3
[ 4.030496] index 14 is out of range for type 'btree_iter_set [4]'
[ 4.030930] CPU: 13 PID: 184 Comm: kworker/13:1 Not tainted
6.5.0-41-generic #41~22.04.2-Ubuntu
[ 4.031841] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
[ 4.032650] Workqueue: events register_cache_worker [bcache]
[ 4.033149] Call Trace:
[ 4.033549] <TASK>
[ 4.033972] dump_stack_lvl+0x48/0x70
[ 4.034418] dump_stack+0x10/0x20
[ 4.034839] __ubsan_handle_out_of_bounds+0xc6/0x110
[ 4.035279] btree_mergesort+0x4d4/0x520 [bcache]
[ 4.035730] ? __pfx_bch_ptr_invalid+0x10/0x10 [bcache]
[ 4.036191] ? __pfx_bch_extent_sort_cmp+0x10/0x10 [bcache]
[ 4.036691] __btree_sort+0x96/0x2d0 [bcache]
[ 4.037182] bch_btree_sort_and_fix_extents+0x1d/0x40 [bcache]
[ 4.037674] bch_btree_node_read_done+0x34d/0x450 [bcache]
[ 4.038172] ? mempool_kfree+0xe/0x20
[ 4.038617] bch_btree_node_read+0xf8/0x1e0 [bcache]
[ 4.039120] ? __pfx_closure_sync_fn+0x10/0x10 [bcache]
[ 4.039659] bch_btree_node_get.part.0+0x160/0x340 [bcache]
[ 4.040220] ? __bch_btree_ptr_invalid+0x60/0xd0 [bcache]
[ 4.040806] ? __pfx_up_write+0x10/0x10
[ 4.041371] bch_btree_node_get+0x16/0x30 [bcache]
[ 4.048339] </TASK>
[ 4.227653] UBSAN: array-index-out-of-bounds in
/build/linux-hwe-6.5-QmAt2N/linux-hwe-6.5-6.5.0/drivers/md/bcache/extents.c:281:4
[ 4.228847] index 4 is out of range for type 'btree_iter_set [4]'
[ 4.229472] CPU: 13 PID: 184 Comm: kworker/13:1 Not tainted
6.5.0-41-generic #41~22.04.2-Ubuntu
[ 4.230680] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
[ 4.231954] Workqueue: events register_cache_worker [bcache]
[ 4.232690] Call Trace:
[ 4.233327] <TASK>
[ 4.233935] dump_stack_lvl+0x48/0x70
[ 4.234568] dump_stack+0x10/0x20
[ 4.235219] __ubsan_handle_out_of_bounds+0xc6/0x110
[ 4.235833] bch_extent_sort_fixup+0xb95/0xd70 [bcache]
[ 4.236524] ? __ubsan_handle_out_of_bounds+0xee/0x110
[ 4.237159] ? __pfx_bch_ptr_invalid+0x10/0x10 [bcache]
[ 4.237839] btree_mergesort+0x221/0x520 [bcache]
[ 4.238823] ? __pfx_bch_ptr_invalid+0x10/0x10 [bcache]
[ 4.239800] __btree_sort+0x96/0x2d0 [bcache]
[ 4.240880] bch_btree_sort_and_fix_extents+0x1d/0x40 [bcache]
[ 4.243046] bch_btree_node_read_done+0x34d/0x450 [bcache]
[ 4.245223] ? mempool_kfree+0xe/0x20
[ 4.246311] bch_btree_node_read+0xf8/0x1e0 [bcache]
[ 4.247410] ? __pfx_closure_sync_fn+0x10/0x10 [bcache]
[ 4.248471] bch_btree_node_get.part.0+0x160/0x340 [bcache]
[ 4.248959] ? __bch_btree_ptr_invalid+0x60/0xd0 [bcache]
[ 4.249454] ? __pfx_up_write+0x10/0x10
[ 4.249904] bch_btree_node_get+0x16/0x30 [bcache]
[ 4.255145] </TASK>
[ 4.257388] UBSAN: array-index-out-of-bounds in
/build/linux-hwe-6.5-QmAt2N/linux-hwe-6.5-6.5.0/drivers/md/bcache/extents.c:36:18
[ 4.258429] index 14 is out of range for type 'btree_iter_set [4]'
[ 4.258964] CPU: 13 PID: 184 Comm: kworker/13:1 Not tainted
6.5.0-41-generic #41~22.04.2-Ubuntu
[ 4.260073] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
[ 4.261188] Workqueue: events register_cache_worker [bcache]
[ 4.261811] Call Trace:
[ 4.262374] <TASK>
[ 4.262912] dump_stack_lvl+0x48/0x70
[ 4.263502] dump_stack+0x10/0x20
[ 4.264042] __ubsan_handle_out_of_bounds+0xc6/0x110
[ 4.264605] bch_extent_sort_fixup+0xbe5/0xd70 [bcache]
[ 4.265218] ? __ubsan_handle_out_of_bounds+0xee/0x110
[ 4.265821] ? __pfx_bch_ptr_invalid+0x10/0x10 [bcache]
[ 4.266514] btree_mergesort+0x221/0x520 [bcache]
[ 4.267234] ? __pfx_bch_ptr_invalid+0x10/0x10 [bcache]
[ 4.267882] __btree_sort+0x96/0x2d0 [bcache]
[ 4.268508] bch_btree_sort_and_fix_extents+0x1d/0x40 [bcache]
[ 4.269144] bch_btree_node_read_done+0x34d/0x450 [bcache]
[ 4.269825] ? mempool_kfree+0xe/0x20
[ 4.270489] bch_btree_node_read+0xf8/0x1e0 [bcache]
[ 4.271243] ? __pfx_closure_sync_fn+0x10/0x10 [bcache]
[ 4.272293] bch_btree_node_get.part.0+0x160/0x340 [bcache]
[ 4.273260] ? __bch_btree_ptr_invalid+0x60/0xd0 [bcache]
[ 4.274182] ? __pfx_up_write+0x10/0x10
[ 4.274973] bch_btree_node_get+0x16/0x30 [bcache]
[ 4.284807] </TASK>
[ 4.286129] UBSAN: array-index-out-of-bounds in
/build/linux-hwe-6.5-QmAt2N/linux-hwe-6.5-6.5.0/drivers/md/bcache/extents.c:291:4
[ 4.286791] index 4 is out of range for type 'btree_iter_set [4]'
[ 4.287231] CPU: 13 PID: 184 Comm: kworker/13:1 Not tainted
6.5.0-41-generic #41~22.04.2-Ubuntu
[ 4.288033] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
[ 4.288863] Workqueue: events register_cache_worker [bcache]
[ 4.289340] Call Trace:
[ 4.289753] <TASK>
[ 4.290168] dump_stack_lvl+0x48/0x70
[ 4.290581] dump_stack+0x10/0x20
[ 4.290984] __ubsan_handle_out_of_bounds+0xc6/0x110
[ 4.291432] bch_extent_sort_fixup+0xb77/0xd70 [bcache]
[ 4.291882] ? __ubsan_handle_out_of_bounds+0xee/0x110
[ 4.292309] ? __pfx_bch_ptr_invalid+0x10/0x10 [bcache]
[ 4.292764] btree_mergesort+0x221/0x520 [bcache]
[ 4.293225] ? __pfx_bch_ptr_invalid+0x10/0x10 [bcache]
[ 4.293683] __btree_sort+0x96/0x2d0 [bcache]
[ 4.294153] bch_btree_sort_and_fix_extents+0x1d/0x40 [bcache]
[ 4.294631] bch_btree_node_read_done+0x34d/0x450 [bcache]
[ 4.295175] ? mempool_kfree+0xe/0x20
[ 4.295671] bch_btree_node_read+0xf8/0x1e0 [bcache]
[ 4.296257] ? __pfx_closure_sync_fn+0x10/0x10 [bcache]
[ 4.296834] bch_btree_node_get.part.0+0x160/0x340 [bcache]
[ 4.297446] ? __bch_btree_ptr_invalid+0x60/0xd0 [bcache]
[ 4.298087] ? __pfx_up_write+0x10/0x10
[ 4.298678] bch_btree_node_get+0x16/0x30 [bcache]
[ 4.306037] </TASK>
[Where problems could occur]
-The patch modifies the way bcache allocates space to the btree
iterator. The main problems that could occur are different UBSAN
warnings showing up that could possibly trigger a crash much easier
than the current array index-out-of-bounds being observed.
Thank you @illwieckz for the original bug report
[original description]
Since I upgraded from lunar to mantic I get a load of those errors (41
on a fresh boot) in dmesg:
```
[ 4.277343] UBSAN: array-index-out-of-bounds in
/build/linux-D15vQj/linux-6.5.0/drivers/md/bcache/bset.c:1098:3
[ 4.277728] index 4 is out of range for type 'btree_iter_set [4]'
[ 4.277925] CPU: 7 PID: 247 Comm: kworker/7:1 Not tainted 6.5.0-9-generic
#9-Ubuntu
[ 4.278132] Hardware name: Default string Default string/Default string,
BIOS WRX80SU8-F6 06/08/2023
[ 4.278531] Workqueue: events register_cache_worker [bcache]
[ 4.278754] Call Trace:
[ 4.278949] <TASK>
[ 4.279143] dump_stack_lvl+0x48/0x70
[ 4.279337] dump_stack+0x10/0x20
[ 4.279526] __ubsan_handle_out_of_bounds+0xc6/0x110
[ 4.279721] bch_btree_iter_push+0x4e6/0x4f0 [bcache]
[ 4.279929] bch_btree_node_read_done+0xcb/0x410 [bcache]
[ 4.280142] bch_btree_node_read+0xf8/0x1e0 [bcache]
[ 4.280349] ? __pfx_closure_sync_fn+0x10/0x10 [bcache]
[ 4.280557] bch_btree_node_get.part.0+0x15c/0x330 [bcache]
[ 4.280764] ? __bch_btree_ptr_invalid+0x66/0xe0 [bcache]
[ 4.280975] ? __pfx_up_write+0x10/0x10
[ 4.281170] bch_btree_node_get+0x16/0x30 [bcache]
[ 4.281375] run_cache_set+0x596/0x850 [bcache]
[ 4.281578] ? srso_return_thunk+0x5/0x10
[ 4.281773] register_cache_set+0x1a2/0x210 [bcache]
[ 4.281984] register_cache+0x11a/0x1a0 [bcache]
[ 4.282187] register_cache_worker+0x22/0x80 [bcache]
[ 4.282387] process_one_work+0x223/0x440
[ 4.282573] worker_thread+0x4d/0x3f0
[ 4.282753] ? srso_return_thunk+0x5/0x10
[ 4.282931] ? _raw_spin_lock_irqsave+0xe/0x20
[ 4.283113] ? __pfx_worker_thread+0x10/0x10
[ 4.283286] kthread+0xf2/0x120
[ 4.283458] ? __pfx_kthread+0x10/0x10
[ 4.283631] ret_from_fork+0x47/0x70
[ 4.283800] ? __pfx_kthread+0x10/0x10
[ 4.283972] ret_from_fork_asm+0x1b/0x30
[ 4.284143] </TASK>
```
This system has 4 bcache backing devices and 4 bcache cache devices,
though they are not associated for now and caching is disabled. It was
already like that when I upgraded, so the kernel only uses the backing
code, not the caching one.
ProblemType: Bug
DistroRelease: Ubuntu 23.10
Package: linux-image-6.5.0-9-generic 6.5.0-9.9
ProcVersionSignature: Ubuntu 6.5.0-9.9-generic 6.5.3
Uname: Linux 6.5.0-9-generic x86_64
ApportVersion: 2.27.0-0ubuntu5
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: GNOME
Date: Sat Oct 14 23:16:33 2023
HibernationDevice: RESUME=none
MachineType: {report['dmi.sys.vendor']} {report['dmi.product.name']}
ProcFB:
0 amdgpudrmfb
1 astdrmfb
ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-6.5.0-9-generic
root=UUID=f35ecf77-511e-4dde-ac11-c1d848e97315 ro rootflags=subvol=@
amdgpu.si_support=1 radeon.si_support=0 amdgpu.cik_support=1
radeon.cik_support=0 amdgpu.exp_hw_support=1 amdgpu.gpu_recovery=1
amdgpu.ppfeaturemask=0xffffffff delayacct zswap.enabled=1
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-6.5.0-9-generic N/A
linux-backports-modules-6.5.0-9-generic N/A
linux-firmware 20230919.git3672ccab-0ubuntu2.1
RfKill:
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/08/2023
dmi.bios.release: 5.23
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: WRX80SU8-F6
dmi.board.asset.tag: Default string
dmi.board.name: Default string
dmi.board.vendor: Default string
dmi.board.version: Default string
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias:
dmi:bvnAmericanMegatrendsInternational,LLC.:bvrWRX80SU8-F6:bd06/08/2023:br5.23:svnDefaultstring:pnDefaultstring:pvrDefaultstring:rvnDefaultstring:rnDefaultstring:rvrDefaultstring:cvnDefaultstring:ct3:cvrDefaultstring:skuDefaultstring:
dmi.product.family: Default string
dmi.product.name: Default string
dmi.product.sku: Default string
dmi.product.version: Default string
dmi.sys.vendor: Default string
modified.conffile..etc.default.apport: [modified]
mtime.conffile..etc.default.apport: 2018-06-16T17:39:00.798346
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