In the Linux kernel, the following vulnerability has been resolved:
gfs2: Set .migrate_folio in gfs2_{rgrp,meta}_aops
Clears up the warning added in 7ee3647243e5 ("migrate: Remove call to
->writepage") that occurs in various xfstests, causing "something found
in dmesg" failures.
[ 341.136573] gfs2_meta_aops does not implement migrate_folio
[ 341.136953] WARNING: CPU: 1 PID: 36 at mm/migrate.c:944 move_to_new_folio+0x2f8/0x300
In the Linux kernel, the following vulnerability has been resolved:
bpf: Forget ranges when refining tnum after JSET
Syzbot reported a kernel warning due to a range invariant violation on
the following BPF program.
0: call bpf_get_netns_cookie
1: if r0 == 0 goto <exit>
2: if r0 & Oxffffffff goto <exit>
The issue is on the path where we fall through both jumps.
That path is unreachable at runtime: after insn 1, we know r0 != 0, but
with the sign extension on the jset, we would only fallthrough insn 2
if r0 == 0. Unfortunately, is_branch_taken() isn't currently able to
figure this out, so the verifier walks all branches. The verifier then
refines the register bounds using the second condition and we end
up with inconsistent bounds on this unreachable path:
1: if r0 == 0 goto <exit>
r0: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0xffffffffffffffff)
2: if r0 & 0xffffffff goto <exit>
r0 before reg_bounds_sync: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0)
r0 after reg_bounds_sync: u64=[0x1, 0] var_off=(0, 0)
Improving the range refinement for JSET to cover all cases is tricky. We
also don't expect many users to rely on JSET given LLVM doesn't generate
those instructions. So instead of improving the range refinement for
JSETs, Eduard suggested we forget the ranges whenever we're narrowing
tnums after a JSET. This patch implements that approach.
In the Linux kernel, the following vulnerability has been resolved:
rcu: Fix rcu_read_unlock() deadloop due to IRQ work
During rcu_read_unlock_special(), if this happens during irq_exit(), we
can lockup if an IPI is issued. This is because the IPI itself triggers
the irq_exit() path causing a recursive lock up.
This is precisely what Xiongfeng found when invoking a BPF program on
the trace_tick_stop() tracepoint As shown in the trace below. Fix by
managing the irq_work state correctly.
irq_exit()
__irq_exit_rcu()
/* in_hardirq() returns false after this */
preempt_count_sub(HARDIRQ_OFFSET)
tick_irq_exit()
tick_nohz_irq_exit()
tick_nohz_stop_sched_tick()
trace_tick_stop() /* a bpf prog is hooked on this trace point */
__bpf_trace_tick_stop()
bpf_trace_run2()
rcu_read_unlock_special()
/* will send a IPI to itself */
irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu);
A simple reproducer can also be obtained by doing the following in
tick_irq_exit(). It will hang on boot without the patch:
static inline void tick_irq_exit(void)
{
+ rcu_read_lock();
+ WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, true);
+ rcu_read_unlock();
+
[neeraj: Apply Frederic's suggested fix for PREEMPT_RT]
In the Linux kernel, the following vulnerability has been resolved:
rcutorture: Fix rcutorture_one_extend_check() splat in RT kernels
For built with CONFIG_PREEMPT_RT=y kernels, running rcutorture
tests resulted in the following splat:
[ 68.797425] rcutorture_one_extend_check during change: Current 0x1 To add 0x1 To remove 0x0 preempt_count() 0x0
[ 68.797533] WARNING: CPU: 2 PID: 512 at kernel/rcu/rcutorture.c:1993 rcutorture_one_extend_check+0x419/0x560 [rcutorture]
[ 68.797601] Call Trace:
[ 68.797602] <TASK>
[ 68.797619] ? lockdep_softirqs_off+0xa5/0x160
[ 68.797631] rcutorture_one_extend+0x18e/0xcc0 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[ 68.797646] ? local_clock+0x19/0x40
[ 68.797659] rcu_torture_one_read+0xf0/0x280 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[ 68.797678] ? __pfx_rcu_torture_one_read+0x10/0x10 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[ 68.797804] ? __pfx_rcu_torture_timer+0x10/0x10 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[ 68.797815] rcu-torture: rcu_torture_reader task started
[ 68.797824] rcu-torture: Creating rcu_torture_reader task
[ 68.797824] rcu_torture_reader+0x238/0x580 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[ 68.797836] ? kvm_sched_clock_read+0x15/0x30
Disable BH does not change the SOFTIRQ corresponding bits in
preempt_count() for RT kernels, this commit therefore use
softirq_count() to check the if BH is disabled.
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Validate i_depth for exhash directories
A fuzzer test introduced corruption that ends up with a depth of 0 in
dir_e_read(), causing an undefined shift by 32 at:
index = hash >> (32 - dip->i_depth);
As calculated in an open-coded way in dir_make_exhash(), the minimum
depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is
invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time.
So we can avoid the undefined behaviour by checking for depth values
lower than the minimum in gfs2_dinode_in(). Values greater than the
maximum are already being checked for there.
Also switch the calculation in dir_make_exhash() to use ilog2() to
clarify how the depth is calculated.
Tested with the syzkaller repro.c and xfstests '-g quick'.
In the Linux kernel, the following vulnerability has been resolved:
rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access
In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.
This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.
This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/pm: fix null pointer access
Writing a string without delimiters (' ', '\n', '\0') to the under
gpu_od/fan_ctrl sysfs or pp_power_profile_mode for the CUSTOM profile
will result in a null pointer dereference.
In the Linux kernel, the following vulnerability has been resolved:
iio: common: st_sensors: Fix use of uninitialize device structs
Throughout the various probe functions &indio_dev->dev is used before it
is initialized. This caused a kernel panic in st_sensors_power_enable()
when the call to devm_regulator_bulk_get_enable() fails and then calls
dev_err_probe() with the uninitialized device.
This seems to only cause a panic with dev_err_probe(), dev_err(),
dev_warn() and dev_info() don't seem to cause a panic, but are fixed
as well.
The issue is reported and traced here: [1]
In the Linux kernel, the following vulnerability has been resolved:
drm/gem: Acquire references on GEM handles for framebuffers
A GEM handle can be released while the GEM buffer object is attached
to a DRM framebuffer. This leads to the release of the dma-buf backing
the buffer object, if any. [1] Trying to use the framebuffer in further
mode-setting operations leads to a segmentation fault. Most easily
happens with driver that use shadow planes for vmap-ing the dma-buf
during a page flip. An example is shown below.
[ 156.791968] ------------[ cut here ]------------
[ 156.796830] WARNING: CPU: 2 PID: 2255 at drivers/dma-buf/dma-buf.c:1527 dma_buf_vmap+0x224/0x430
[...]
[ 156.942028] RIP: 0010:dma_buf_vmap+0x224/0x430
[ 157.043420] Call Trace:
[ 157.045898] <TASK>
[ 157.048030] ? show_trace_log_lvl+0x1af/0x2c0
[ 157.052436] ? show_trace_log_lvl+0x1af/0x2c0
[ 157.056836] ? show_trace_log_lvl+0x1af/0x2c0
[ 157.061253] ? drm_gem_shmem_vmap+0x74/0x710
[ 157.065567] ? dma_buf_vmap+0x224/0x430
[ 157.069446] ? __warn.cold+0x58/0xe4
[ 157.073061] ? dma_buf_vmap+0x224/0x430
[ 157.077111] ? report_bug+0x1dd/0x390
[ 157.080842] ? handle_bug+0x5e/0xa0
[ 157.084389] ? exc_invalid_op+0x14/0x50
[ 157.088291] ? asm_exc_invalid_op+0x16/0x20
[ 157.092548] ? dma_buf_vmap+0x224/0x430
[ 157.096663] ? dma_resv_get_singleton+0x6d/0x230
[ 157.101341] ? __pfx_dma_buf_vmap+0x10/0x10
[ 157.105588] ? __pfx_dma_resv_get_singleton+0x10/0x10
[ 157.110697] drm_gem_shmem_vmap+0x74/0x710
[ 157.114866] drm_gem_vmap+0xa9/0x1b0
[ 157.118763] drm_gem_vmap_unlocked+0x46/0xa0
[ 157.123086] drm_gem_fb_vmap+0xab/0x300
[ 157.126979] drm_atomic_helper_prepare_planes.part.0+0x487/0xb10
[ 157.133032] ? lockdep_init_map_type+0x19d/0x880
[ 157.137701] drm_atomic_helper_commit+0x13d/0x2e0
[ 157.142671] ? drm_atomic_nonblocking_commit+0xa0/0x180
[ 157.147988] drm_mode_atomic_ioctl+0x766/0xe40
[...]
[ 157.346424] ---[ end trace 0000000000000000 ]---
Acquiring GEM handles for the framebuffer's GEM buffer objects prevents
this from happening. The framebuffer's cleanup later puts the handle
references.
Commit 1a148af06000 ("drm/gem-shmem: Use dma_buf from GEM object
instance") triggers the segmentation fault easily by using the dma-buf
field more widely. The underlying issue with reference counting has
been present before.
v2:
- acquire the handle instead of the BO (Christian)
- fix comment style (Christian)
- drop the Fixes tag (Christian)
- rename err_ gotos
- add missing Link tag