From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-98511: drm/nouveau: don't bump pin count on failed re-pin in nouveau_bo_pin_locked()
Date: Sun, 18 Oct 2026 17:16:15 +0200 [thread overview]
Message-ID: <2026101820-CVE-2026-98511-aa3c@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau: don't bump pin count on failed re-pin in nouveau_bo_pin_locked()
nouveau_bo_pin_locked() checks whether an already pinned BO is in a
memory domain compatible with a new pin request. When the domains are
incompatible, it sets -EBUSY but still calls ttm_bo_pin() before
returning.
Callers treat a failed nouveau_bo_pin() as not having acquired a new pin,
so the extra pin count is never decreased by a matching unpin.
This triggers the warning in ttm_bo_release():
WARN_ON_ONCE(bo->pin_count);
Found when fuzzing the nouveau driver with a modified Syzkaller:
WARNING: drivers/gpu/drm/ttm/ttm_bo.c:256 at ttm_bo_release+0x827/0x9e0 drivers/gpu/drm/ttm/ttm_bo.c:256, CPU#1: syz.3.24/2212
Modules linked in:
CPU: 1 UID: 0 PID: 2212 Comm: syz.3.24 Not tainted 7.2.0 #24 PREEMPT(lazy)
nouveau 0000:01:00.0: gsp:msg fn:103 len:0x40/0x20 res:0x19 resp:0x19
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:ttm_bo_release+0x827/0x9e0 drivers/gpu/drm/ttm/ttm_bo.c:256
Code: 02 00 0f 85 51 01 00 00 48 8b 7b 08 e8 d2 20 01 00 e9 80 fd ff ff e8 d8 15 c0 fe 90 0f 0b 90 e9 e1 f8 ff ff e8 ca 15 c0 fe 90 <0f> 0b 90 e9 a4 f8 ff ff e8 bc 15 c0 fe be 03 00 00 00 4c 89 e7 e8
msg: 00000000: 05 00 d0 c1 04 00 f0 f1 01 30 00 00 2d 90 00 00 .........0..-...
RSP: 0018:ffffc9000f5cf710 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888018e5d2a8 RCX: ffffffff82bb1b36
RDX: ffff888017b68000 RSI: 0000000000000004 RDI: ffff888018e5d2a8
msg: 00000010: 19 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
RBP: ffff88801261c720 R08: 0000000000000001 R09: ffffed10031cba55
R10: ffff888018e5d2ab R11: 00000000000000f3 R12: ffff888018e5d290
R13: ffff888018e5d2d4 R14: ffff88801b219c18 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880e0f6f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31223ffc CR3: 0000000028e00005 CR4: 0000000000770ef0
PKRU: 80000000
Call Trace:
<TASK>
kref_put include/linux/kref.h:65 [inline]
ttm_bo_put drivers/gpu/drm/ttm/ttm_bo.c:325 [inline]
ttm_bo_fini+0x55/0x80 drivers/gpu/drm/ttm/ttm_bo.c:330
nouveau_gem_object_del+0xb2/0x1b0 drivers/gpu/drm/nouveau/nouveau_gem.c:90
drm_gem_object_free+0x5f/0x90 drivers/gpu/drm/drm_gem.c:1165
kref_put include/linux/kref.h:65 [inline]
__drm_gem_object_put include/drm/drm_gem.h:562 [inline]
drm_gem_object_put include/drm/drm_gem.h:575 [inline]
nouveau_abi16_chan_fini.constprop.0+0x44f/0x5a0 drivers/gpu/drm/nouveau/nouveau_abi16.c:195
nouveau 0000:01:00.0: syz.2.23[2209]: Unknown handle 0x00000000
nouveau_abi16_fini+0x1d0/0x340 drivers/gpu/drm/nouveau/nouveau_abi16.c:225
nouveau_drm_postclose+0x18b/0x3e0 drivers/gpu/drm/nouveau/nouveau_drm.c:1284
nouveau 0000:01:00.0: syz.2.23[2209]: validate_init
drm_file_free.part.0+0x6d6/0xb60 drivers/gpu/drm/drm_file.c:267
drm_file_free drivers/gpu/drm/drm_file.c:237 [inline]
drm_close_helper.isra.0+0x11a/0x160 drivers/gpu/drm/drm_file.c:290
drm_release+0x1ab/0x330 drivers/gpu/drm/drm_file.c:438
__fput+0x39c/0xa60 fs/file_table.c:512
nouveau 0000:01:00.0: syz.2.23[2209]: validate: -2
task_work_run+0x15a/0x230 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x82b/0x25a0 kernel/exit.c:1009
do_group_exit+0xc2/0x280 kernel/exit.c:1152
get_signal+0x1d6e/0x1f30 kernel/signal.c:3046
arch_do_signal_or_restart+0x7d/0x6e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0xdf/0x440 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x4f8/0x690 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f12bac8594d
Code: Unable to access opcode bytes at 0x7f12bac85923.
RSP: 002b:00007f12b96e70d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f12baf15fa8 RCX: 00007f12bac8594d
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f12baf15fac
RBP: 00007f12baf15fa0 R08: 00007f12baee8000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f12baf16038 R14: 0000000000000006 R15: 00007ffe2ed394b0
</TASK>
irq event stamp: 47867
hardirqs last enabled at (47883): [<ffffffff815cafc6>] __up_console_sem+0x66/0x70 kernel/printk/printk.c:347
hardirqs last disabled at (47892): [<ffffffff815cafab>] __up_console_sem+0x4b/0x70 kernel/printk/printk.c:345
softirqs last enabled at (47880): [<ffffffff81434277>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last enabled at (47880): [<ffffffff81434277>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last enabled at (47880): [<ffffffff81434277>] __irq_exit_rcu+0x137/0x1c0 kernel/softirq.c:735
softirqs last disabled at (47875): [<ffffffff81434277>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last disabled at (47875): [<ffffffff81434277>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last disabled at (47875): [<ffffffff81434277>] __irq_exit_rcu+0x137/0x1c0 kernel/softirq.c:735
Fix by calling ttm_bo_pin() only when the existing placement is compatible
with the new pin request. This matches the correct behavior in other DRM
drivers such as amdgpu_bo_pin() in amdgpu.
The Linux kernel CVE team has assigned CVE-2026-98511 to this issue.
Affected and fixed versions
===========================
Issue introduced in 3.19 with commit ad76b3f7c7a0836e74ac0e316e03988ef3c43564 and fixed in 5.15.222 with commit a6e755acf85793a7b4d29ba27b5421af1087263f
Issue introduced in 3.19 with commit ad76b3f7c7a0836e74ac0e316e03988ef3c43564 and fixed in 6.1.189 with commit 5cb7109f0f5f1b47b172e2d5b868d4ce3ae687f8
Issue introduced in 3.19 with commit ad76b3f7c7a0836e74ac0e316e03988ef3c43564 and fixed in 6.6.158 with commit 9924c1d64405be8d10b906368dfb1cfe0d0c6bf0
Issue introduced in 3.19 with commit ad76b3f7c7a0836e74ac0e316e03988ef3c43564 and fixed in 6.12.112 with commit 73c7093e6cc1e6b181a79e16eccc4b8d4f34d8ee
Issue introduced in 3.19 with commit ad76b3f7c7a0836e74ac0e316e03988ef3c43564 and fixed in 6.18.55 with commit 19f5a5839b308697824ff46e6213a2b4cb677771
Issue introduced in 3.19 with commit ad76b3f7c7a0836e74ac0e316e03988ef3c43564 and fixed in 7.2.9 with commit 189ffc7b6cad6390c0695031cb6c7c63472981e8
Issue introduced in 3.19 with commit ad76b3f7c7a0836e74ac0e316e03988ef3c43564 and fixed in 7.3-rc5 with commit 6a6870d3077faa501ca97760057ddca22b68418d
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2026-98511
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
drivers/gpu/drm/nouveau/nouveau_bo.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/a6e755acf85793a7b4d29ba27b5421af1087263f
https://git.kernel.org/stable/c/5cb7109f0f5f1b47b172e2d5b868d4ce3ae687f8
https://git.kernel.org/stable/c/9924c1d64405be8d10b906368dfb1cfe0d0c6bf0
https://git.kernel.org/stable/c/73c7093e6cc1e6b181a79e16eccc4b8d4f34d8ee
https://git.kernel.org/stable/c/19f5a5839b308697824ff46e6213a2b4cb677771
https://git.kernel.org/stable/c/189ffc7b6cad6390c0695031cb6c7c63472981e8
https://git.kernel.org/stable/c/6a6870d3077faa501ca97760057ddca22b68418d
reply other threads:[~2026-10-18 15:24 UTC|newest]
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