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Rob Clark de651b6e04 drm/msm: Fix refcnt underflow in error path
If we hit an error path in GEM obj creation before msm_gem_new_handle()
updates obj->resv to point to the gpuvm resv object, then obj->resv
still points to &obj->_resv.  In this case we don't want to decrement
the refcount of the object being freed (since the refcnt is already
zero).  This fixes the following splat:

   ------------[ cut here ]------------
   refcount_t: underflow; use-after-free.
   WARNING: CPU: 9 PID: 7013 at lib/refcount.c:28 refcount_warn_saturate+0xf4/0x148
   Modules linked in: uinput snd_seq_dummy snd_hrtimer aes_ce_ccm snd_soc_wsa884x regmap_sdw q6prm_clocks q6apm_lpass_da>
    qcom_pil_info i2c_hid drm_kms_helper qcom_common qcom_q6v5 phy_snps_eusb2 qcom_geni_serial drm qcom_sysmon pinctrl_s>
   CPU: 9 UID: 1000 PID: 7013 Comm: deqp-vk Not tainted 6.16.0-rc4-debug+ #25 PREEMPT(voluntary)
   Hardware name: LENOVO 83ED/LNVNB161216, BIOS NHCN53WW 08/02/2024
   pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
   pc : refcount_warn_saturate+0xf4/0x148
   lr : refcount_warn_saturate+0xf4/0x148
   sp : ffff8000a2073920
   x29: ffff8000a2073920 x28: 0000000000000010 x27: 0000000000000010
   x26: 0000000000000042 x25: ffff000810e09800 x24: 0000000000000010
   x23: ffff8000a2073b94 x22: ffff000ddb22de00 x21: ffff000ddb22dc00
   x20: ffff000ddb22ddf8 x19: ffff0008024934e0 x18: 000000000000000a
   x17: 0000000000000000 x16: ffff9f8c67d77340 x15: 0000000000000000
   x14: 00000000ffffffff x13: 2e656572662d7265 x12: 7466612d65737520
   x11: 3b776f6c66726564 x10: 00000000ffff7fff x9 : ffff9f8c67506c70
   x8 : ffff9f8c69fa26f0 x7 : 00000000000bffe8 x6 : c0000000ffff7fff
   x5 : ffff000f53e14548 x4 : ffff6082ea2b2000 x3 : ffff0008b86ab080
   x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0008b86ab080
   Call trace:
    refcount_warn_saturate+0xf4/0x148 (P)
    msm_gem_free_object+0x248/0x260 [msm]
    drm_gem_object_free+0x24/0x40 [drm]
    msm_gem_new+0x1c4/0x1e0 [msm]
    msm_gem_new_handle+0x3c/0x1a0 [msm]
    msm_ioctl_gem_new+0x38/0x70 [msm]
    drm_ioctl_kernel+0xc8/0x138 [drm]
    drm_ioctl+0x2c8/0x618 [drm]
    __arm64_sys_ioctl+0xac/0x108
    invoke_syscall.constprop.0+0x64/0xe8
    el0_svc_common.constprop.0+0x40/0xe8
    do_el0_svc+0x24/0x38
    el0_svc+0x54/0x1d8
    el0t_64_sync_handler+0x10c/0x138
    el0t_64_sync+0x19c/0x1a0
   irq event stamp: 3698694
   hardirqs last  enabled at (3698693): [<ffff9f8c675021dc>] __up_console_sem+0x74/0x90
   hardirqs last disabled at (3698694): [<ffff9f8c68ce8164>] el1_dbg+0x24/0x90
   softirqs last  enabled at (3697578): [<ffff9f8c6744ec5c>] handle_softirqs+0x454/0x4b0
   softirqs last disabled at (3697567): [<ffff9f8c67360244>] __do_softirq+0x1c/0x28
   ---[ end trace 0000000000000000 ]---

Fixes: b58e12a66e ("drm/msm: Add _NO_SHARE flag")
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/665355/
2025-08-01 10:52:33 -07:00
arch drm-misc-next for 6.17: 2025-06-27 09:58:05 +10:00
block block-6.16-20250614 2025-06-14 09:25:22 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: hkdf - move to late_initcall 2025-06-11 10:59:45 +08:00
Documentation dt-bindings: opp: adreno: Update regex of OPP entry 2025-07-04 11:09:43 -07:00
drivers drm/msm: Fix refcnt underflow in error path 2025-08-01 10:52:33 -07:00
fs three smb3 client fixes 2025-06-14 10:13:32 -07:00
include soc: qcom: ubwc: Add #defines for UBWC swizzle bits 2025-07-04 17:48:40 -07:00
init init: fix build warnings about export.h 2025-06-11 22:42:36 -07:00
io_uring io_uring-6.16-20250614 2025-06-14 08:44:54 -07:00
ipc - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
kernel posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del() 2025-06-13 10:55:49 -07:00
lib scatterlist: fix extraneous '@'-sign kernel-doc notation 2025-06-11 22:42:35 -07:00
LICENSES LICENSES: add CC0-1.0 license text 2025-05-21 14:54:17 +02:00
mm 9 hotfixes. 3 are cc:stable and the remainder address post-6.15 issues 2025-06-14 08:18:09 -07:00
net Including fixes from bluetooth and wireless. 2025-06-12 09:50:36 -07:00
rust Rust fixes for v6.16 2025-06-14 08:38:34 -07:00
samples - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
scripts gendwarfksyms: Fix structure type overrides 2025-06-16 00:49:48 +09:00
security KEYS: Invert FINAL_PUT bit 2025-06-11 11:57:14 -07:00
sound treewide, timers: Rename from_timer() to timer_container_of() 2025-06-08 09:07:37 +02:00
tools 9 hotfixes. 3 are cc:stable and the remainder address post-6.15 issues 2025-06-14 08:18:09 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge branch 'kvm-lockdep-common' into HEAD 2025-05-28 06:29:17 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore Python compiled bytecode 2025-04-24 10:12:46 -06:00
.mailmap Including fixes from bluetooth and wireless. 2025-06-12 09:50:36 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml
COPYING
CREDITS Update Christoph's Email address and make it consistent 2025-05-12 23:50:31 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS drm-misc-next for 6.17: 2025-06-18 08:09:35 +10:00
Makefile Linux 6.16-rc2 2025-06-15 13:49:41 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.