Since Linux v6.7, booting using BootX on an Old World PowerMac produces
an early crash. Stan Johnson writes, "the symptoms are that the screen
goes blank and the backlight stays on, and the system freezes (Linux
doesn't boot)."
Further testing revealed that the failure can be avoided by disabling
CONFIG_BOOTX_TEXT. Bisection revealed that the regression was caused by
a change to the font bitmap pointer that's used when btext_init() begins
painting characters on the display, early in the boot process.
Christophe Leroy explains, "before kernel text is relocated to its final
location ... data is addressed with an offset which is added to the
Global Offset Table (GOT) entries at the start of bootx_init()
by function reloc_got2(). But the pointers that are located inside a
structure are not referenced in the GOT and are therefore not updated by
reloc_got2(). It is therefore needed to apply the offset manually by using
PTRRELOC() macro."
Cc: Cedar Maxwell <cedarmaxwell(a)mac.com>
Cc: Stan Johnson <userm57(a)yahoo.com>
Cc: "Dr. David Alan Gilbert" <linux(a)treblig.org>
Cc: Benjamin Herrenschmidt <benh(a)kernel.crashing.org>
Cc: stable(a)vger.kernel.org
Link: https://lists.debian.org/debian-powerpc/2025/10/msg00111.html
Link: https://lore.kernel.org/linuxppc-dev/d81ddca8-c5ee-d583-d579-02b19ed95301@y…
Reported-by: Cedar Maxwell <cedarmaxwell(a)mac.com>
Closes: https://lists.debian.org/debian-powerpc/2025/09/msg00031.html
Bisected-by: Stan Johnson <userm57(a)yahoo.com>
Tested-by: Stan Johnson <userm57(a)yahoo.com>
Fixes: 0ebc7feae79a ("powerpc: Use shared font data")
Suggested-by: Christophe Leroy <christophe.leroy(a)csgroup.eu>
Signed-off-by: Finn Thain <fthain(a)linux-m68k.org>
---
Changed since v1:
- Improved commit log entry to better explain the need for PTRRELOC().
---
arch/powerpc/kernel/btext.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/btext.c b/arch/powerpc/kernel/btext.c
index 7f63f1cdc6c3..ca00c4824e31 100644
--- a/arch/powerpc/kernel/btext.c
+++ b/arch/powerpc/kernel/btext.c
@@ -20,6 +20,7 @@
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/udbg.h>
+#include <asm/setup.h>
#define NO_SCROLL
@@ -463,7 +464,7 @@ static noinline void draw_byte(unsigned char c, long locX, long locY)
{
unsigned char *base = calc_base(locX << 3, locY << 4);
unsigned int font_index = c * 16;
- const unsigned char *font = font_sun_8x16.data + font_index;
+ const unsigned char *font = PTRRELOC(font_sun_8x16.data) + font_index;
int rb = dispDeviceRowBytes;
rmci_maybe_on();
--
2.49.1
KVM currenty fails a nested VMRUN and injects VMEXIT_INVALID (aka
SVM_EXIT_ERR) if L1 sets NP_ENABLE and the host does not support NPTs.
On first glance, it seems like the check should actually be for
guest_cpu_cap_has(X86_FEATURE_NPT) instead, as it is possible for the
host to support NPTs but the guest CPUID to not advertise it.
However, the consistency check is not architectural to begin with. The
APM does not mention VMEXIT_INVALID if NP_ENABLE is set on a processor
that does not have X86_FEATURE_NPT. Hence, NP_ENABLE should be ignored
if X86_FEATURE_NPT is not available for L1. Apart from the consistency
check, this is currently the case because NP_ENABLE is actually copied
from VMCB01 to VMCB02, not from VMCB12.
On the other hand, the APM does mention two other consistency checks for
NP_ENABLE, both of which are missing (paraphrased):
In Volume #2, 15.25.3 (24593—Rev. 3.42—March 2024):
If VMRUN is executed with hCR0.PG cleared to zero and NP_ENABLE set to
1, VMRUN terminates with #VMEXIT(VMEXIT_INVALID)
In Volume #2, 15.25.4 (24593—Rev. 3.42—March 2024):
When VMRUN is executed with nested paging enabled (NP_ENABLE = 1), the
following conditions are considered illegal state combinations, in
addition to those mentioned in “Canonicalization and Consistency
Checks”:
• Any MBZ bit of nCR3 is set.
• Any G_PAT.PA field has an unsupported type encoding or any
reserved field in G_PAT has a nonzero value.
Replace the existing consistency check with consistency checks on
hCR0.PG and nCR3. Only perform the consistency checks if L1 has
X86_FEATURE_NPT and NP_ENABLE is set in VMCB12. The G_PAT consistency
check will be addressed separately.
As it is now possible for an L1 to run L2 with NP_ENABLE set but
ignored, also check that L1 has X86_FEATURE_NPT in nested_npt_enabled().
Pass L1's CR0 to __nested_vmcb_check_controls(). In
nested_vmcb_check_controls(), L1's CR0 is available through
kvm_read_cr0(), as vcpu->arch.cr0 is not updated to L2's CR0 until later
through nested_vmcb02_prepare_save() -> svm_set_cr0().
In svm_set_nested_state(), L1's CR0 is available in the captured save
area, as svm_get_nested_state() captures L1's save area when running L2,
and L1's CR0 is stashed in VMCB01 on nested VMRUN (in
nested_svm_vmrun()).
Fixes: 4b16184c1cca ("KVM: SVM: Initialize Nested Nested MMU context on VMRUN")
Cc: stable(a)vger.kernel.org
Signed-off-by: Yosry Ahmed <yosry.ahmed(a)linux.dev>
---
arch/x86/kvm/svm/nested.c | 21 ++++++++++++++++-----
arch/x86/kvm/svm/svm.h | 3 ++-
2 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 74211c5c68026..87bcc5eff96e8 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -325,7 +325,8 @@ static bool nested_svm_check_bitmap_pa(struct kvm_vcpu *vcpu, u64 pa, u32 size)
}
static bool __nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
- struct vmcb_ctrl_area_cached *control)
+ struct vmcb_ctrl_area_cached *control,
+ unsigned long l1_cr0)
{
if (CC(!vmcb12_is_intercept(control, INTERCEPT_VMRUN)))
return false;
@@ -333,8 +334,12 @@ static bool __nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
if (CC(control->asid == 0))
return false;
- if (CC((control->nested_ctl & SVM_NESTED_CTL_NP_ENABLE) && !npt_enabled))
- return false;
+ if (nested_npt_enabled(to_svm(vcpu))) {
+ if (CC(!kvm_vcpu_is_legal_gpa(vcpu, control->nested_cr3)))
+ return false;
+ if (CC(!(l1_cr0 & X86_CR0_PG)))
+ return false;
+ }
if (CC(!nested_svm_check_bitmap_pa(vcpu, control->msrpm_base_pa,
MSRPM_SIZE)))
@@ -400,7 +405,12 @@ static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);
struct vmcb_ctrl_area_cached *ctl = &svm->nested.ctl;
- return __nested_vmcb_check_controls(vcpu, ctl);
+ /*
+ * Make sure we did not enter guest mode yet, in which case
+ * kvm_read_cr0() could return L2's CR0.
+ */
+ WARN_ON_ONCE(is_guest_mode(vcpu));
+ return __nested_vmcb_check_controls(vcpu, ctl, kvm_read_cr0(vcpu));
}
static
@@ -1831,7 +1841,8 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
ret = -EINVAL;
__nested_copy_vmcb_control_to_cache(vcpu, &ctl_cached, ctl);
- if (!__nested_vmcb_check_controls(vcpu, &ctl_cached))
+ /* 'save' contains L1 state saved from before VMRUN */
+ if (!__nested_vmcb_check_controls(vcpu, &ctl_cached, save->cr0))
goto out_free;
/*
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index f6fb70ddf7272..3e805a43ffcdb 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -552,7 +552,8 @@ static inline bool gif_set(struct vcpu_svm *svm)
static inline bool nested_npt_enabled(struct vcpu_svm *svm)
{
- return svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE;
+ return guest_cpu_cap_has(&svm->vcpu, X86_FEATURE_NPT) &&
+ svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE;
}
static inline bool nested_vnmi_enabled(struct vcpu_svm *svm)
--
2.51.2.1041.gc1ab5b90ca-goog
On hardware based on Toradex Verdin AM62 the recovery mechanism added by
commit ad5c6ecef27e ("drm: bridge: ti-sn65dsi83: Add error recovery
mechanism") has been reported [0] to make the display turn on and off and
and the kernel logging "Unexpected link status 0x01".
According to the report, the error recovery mechanism is triggered by the
PLL_UNLOCK error going active. Analysis suggested the board is unable to
provide the correct DSI clock neede by the SN65DSI84, to which the TI
SN65DSI84 reacts by raising the PLL_UNLOCK, while the display still works
apparently without issues.
On other hardware, where all the clocks are within the components
specifications, the PLL_UNLOCK bit does not trigger while the display is in
normal use. It can trigger for e.g. electromagnetic interference, which is
a transient event and exactly the reason why the error recovery mechanism
has been implemented.
Idelly the PLL_UNLOCK bit could be ignored when working out of
specification, but this requires to detect in software whether it triggers
because the device is working out of specification but visually correctly
for the user or for good reasons (e.g. EMI, or even because working out of
specifications but compromising the visual output).
The ongoing analysis as of this writing [1][2] has not yet found a way for
the driver to discriminate among the two cases. So as a temporary measure
mask the PLL_UNLOCK error bit unconditionally.
[0] https://lore.kernel.org/r/bhkn6hley4xrol5o3ytn343h4unkwsr26p6s6ltcwexnrsjsd…
[1] https://lore.kernel.org/all/b71e941c-fc8a-4ac1-9407-0fe7df73b412@gmail.com/
[2] https://lore.kernel.org/all/20251125103900.31750-1-francesco@dolcini.it/
Closes: https://lore.kernel.org/r/bhkn6hley4xrol5o3ytn343h4unkwsr26p6s6ltcwexnrsjsd…
Cc: stable(a)vger.kernel.org # 6.15+
Co-developed-by: Hervé Codina <herve.codina(a)bootlin.com>
Signed-off-by: Hervé Codina <herve.codina(a)bootlin.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli(a)bootlin.com>
---
Francesco, Emanuele, João: can you please apply this patch and report
whether the display on the affected boards gets back to working as before?
Cc: João Paulo Gonçalves <jpaulo.silvagoncalves(a)gmail.com>
Cc: Francesco Dolcini <francesco(a)dolcini.it>
Cc: Emanuele Ghidoli <ghidoliemanuele(a)gmail.com>
---
drivers/gpu/drm/bridge/ti-sn65dsi83.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
index 033c44326552..fffb47b62f43 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
@@ -429,7 +429,14 @@ static void sn65dsi83_handle_errors(struct sn65dsi83 *ctx)
*/
ret = regmap_read(ctx->regmap, REG_IRQ_STAT, &irq_stat);
- if (ret || irq_stat) {
+
+ /*
+ * Some hardware (Toradex Verdin AM62) is known to report the
+ * PLL_UNLOCK error interrupt while working without visible
+ * problems. In lack of a reliable way to discriminate such cases
+ * from user-visible PLL_UNLOCK cases, ignore that bit entirely.
+ */
+ if (ret || irq_stat & ~REG_IRQ_STAT_CHA_PLL_UNLOCK) {
/*
* IRQ acknowledged is not always possible (the bridge can be in
* a state where it doesn't answer anymore). To prevent an
@@ -654,7 +661,7 @@ static void sn65dsi83_atomic_enable(struct drm_bridge *bridge,
if (ctx->irq) {
/* Enable irq to detect errors */
regmap_write(ctx->regmap, REG_IRQ_GLOBAL, REG_IRQ_GLOBAL_IRQ_EN);
- regmap_write(ctx->regmap, REG_IRQ_EN, 0xff);
+ regmap_write(ctx->regmap, REG_IRQ_EN, 0xff & ~REG_IRQ_EN_CHA_PLL_UNLOCK_EN);
} else {
/* Use the polling task */
sn65dsi83_monitor_start(ctx);
---
base-commit: c884ee70b15a8d63184d7c1e02eba99676a6fcf7
change-id: 20251126-drm-ti-sn65dsi83-ignore-pll-unlock-4a28aa29eb5c
Best regards,
--
Luca Ceresoli <luca.ceresoli(a)bootlin.com>
The vdd_mpu regulator maximum voltage was previously limited to 1.2985V,
which prevented the CPU from reaching the 1GHz operating point. This
limitation was put in place because voltage changes were not working
correctly, causing the board to stall when attempting higher frequencies.
Increase the maximum voltage to 1.3515V to allow the full 1GHz OPP to be
used.
Add a TPS65219 PMIC driver fixes that properly implement the LOCK register
handling, to make voltage transitions work reliably.
Changes in v4:
- Move the registers unlock in the probe instead of a custom regmap write
operation.
- Link to v3: https://lore.kernel.org/r/20251112-fix_tps65219-v3-0-e49bab4c01ce@bootlin.c…
Changes in v3:
- Remove an unused variable
- Link to v2: https://lore.kernel.org/r/20251106-fix_tps65219-v2-0-a7d608c4272f@bootlin.c…
Changes in v2:
- Setup a custom regmap_bus only for the TPS65214 instead of checking
the chip_id every time reg_write is called.
- Add the am335x-bonegreen-eco devicetree change in the same patch
series.
Signed-off-by: Kory Maincent (TI.com) <kory.maincent(a)bootlin.com>
---
Kory Maincent (TI.com) (2):
mfd: tps65219: Implement LOCK register handling for TPS65214
ARM: dts: am335x-bonegreen-eco: Enable 1GHz OPP by increasing vdd_mpu voltage
arch/arm/boot/dts/ti/omap/am335x-bonegreen-eco.dts | 2 +-
drivers/mfd/tps65219.c | 7 +++++++
include/linux/mfd/tps65219.h | 2 ++
3 files changed, 10 insertions(+), 1 deletion(-)
---
base-commit: 1c353dc8d962de652bc7ad2ba2e63f553331391c
change-id: 20251106-fix_tps65219-dd62141d22cf
Best regards,
--
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
When the SLAB_STORE_USER debug flag is used, any metadata placed after
the original kmalloc request size (orig_size) is not properly aligned
on 64-bit architectures because its type is unsigned int. When both KASAN
and SLAB_STORE_USER are enabled, kasan_alloc_meta is misaligned.
Note that 64-bit architectures without HAVE_EFFICIENT_UNALIGNED_ACCESS
are assumed to require 64-bit accesses to be 64-bit aligned.
See HAVE_64BIT_ALIGNED_ACCESS and commit adab66b71abf ("Revert:
"ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS"") for more details.
Because not all architectures support unaligned memory accesses,
ensure that all metadata (track, orig_size, kasan_{alloc,free}_meta)
in a slab object are word-aligned. struct track, kasan_{alloc,free}_meta
are aligned by adding __aligned(__alignof__(unsigned long)).
For orig_size, use ALIGN(sizeof(unsigned int), sizeof(unsigned long)) to
make clear that its size remains unsigned int but it must be aligned to
a word boundary. On 64-bit architectures, this reserves 8 bytes for
orig_size, which is acceptable since kmalloc's original request size
tracking is intended for debugging rather than production use.
Cc: stable(a)vger.kernel.org
Fixes: 6edf2576a6cc ("mm/slub: enable debugging memory wasting of kmalloc")
Acked-by: Andrey Konovalov <andreyknvl(a)gmail.com>
Signed-off-by: Harry Yoo <harry.yoo(a)oracle.com>
---
v1 -> v2:
- Added Andrey's Acked-by.
- Added references to HAVE_64BIT_ALIGNED_ACCESS and the commit that
resurrected it.
- Used __alignof__() instead of sizeof(), as suggested by Pedro (off-list).
Note: either __alignof__ or sizeof() produces the exactly same mm/slub.o
files, so there's no functional difference.
Thanks!
mm/kasan/kasan.h | 4 ++--
mm/slub.c | 16 +++++++++++-----
2 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 129178be5e64..b86b6e9f456a 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -265,7 +265,7 @@ struct kasan_alloc_meta {
struct kasan_track alloc_track;
/* Free track is stored in kasan_free_meta. */
depot_stack_handle_t aux_stack[2];
-};
+} __aligned(__alignof__(unsigned long));
struct qlist_node {
struct qlist_node *next;
@@ -289,7 +289,7 @@ struct qlist_node {
struct kasan_free_meta {
struct qlist_node quarantine_link;
struct kasan_track free_track;
-};
+} __aligned(__alignof__(unsigned long));
#endif /* CONFIG_KASAN_GENERIC */
diff --git a/mm/slub.c b/mm/slub.c
index a585d0ac45d4..462a39d57b3a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -344,7 +344,7 @@ struct track {
int cpu; /* Was running on cpu */
int pid; /* Pid context */
unsigned long when; /* When did the operation occur */
-};
+} __aligned(__alignof__(unsigned long));
enum track_item { TRACK_ALLOC, TRACK_FREE };
@@ -1196,7 +1196,7 @@ static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
off += 2 * sizeof(struct track);
if (slub_debug_orig_size(s))
- off += sizeof(unsigned int);
+ off += ALIGN(sizeof(unsigned int), __alignof__(unsigned long));
off += kasan_metadata_size(s, false);
@@ -1392,7 +1392,8 @@ static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
off += 2 * sizeof(struct track);
if (s->flags & SLAB_KMALLOC)
- off += sizeof(unsigned int);
+ off += ALIGN(sizeof(unsigned int),
+ __alignof__(unsigned long));
}
off += kasan_metadata_size(s, false);
@@ -7820,9 +7821,14 @@ static int calculate_sizes(struct kmem_cache_args *args, struct kmem_cache *s)
*/
size += 2 * sizeof(struct track);
- /* Save the original kmalloc request size */
+ /*
+ * Save the original kmalloc request size.
+ * Although the request size is an unsigned int,
+ * make sure that is aligned to word boundary.
+ */
if (flags & SLAB_KMALLOC)
- size += sizeof(unsigned int);
+ size += ALIGN(sizeof(unsigned int),
+ __alignof__(unsigned long));
}
#endif
--
2.43.0
Hi,
I would like to request backporting commit b441cf3f8c4b ("xfrm: delete
x->tunnel as we delete x") to all LTS kernels.
This patch actually fixes a use-after-free issue, but it hasn't been
backported to any of the LTS versions, which are still being affected.
As the patch describes, a specific trigger scenario could be:
If a tunnel packet is received (e.g., in ip_local_deliver()), with the
outer layer being IPComp protocol and the inner layer being fragmented
packets, during outer packet processing, it will go through xfrm_input()
to hold a reference to the IPComp xfrm_state. Then, it is re-injected into
the network stack via gro_cells_receive() and placed in the reassembly
queue. When exiting the netns and calling cleanup_net(), although
ipv4_frags_exit_net() is called before xfrm_net_exit(), due to asynchronous
scheduling, fqdir_free_work() may execute after xfrm_state_fini().
In xfrm_state_fini(), xfrm_state_flush() puts and deletes the xfrm_state
for IPPROTO_COMP, but does not delete the xfrm_state for IPPROTO_IPIP.
Meanwhile, the skb in the reassembly queue holds the last reference to the
IPPROTO_COMP xfrm_state, so it isn't destroyed yet. Only when the skb in
the reassembly queue is destroyed does the IPPROTO_COMP xfrm_state get
fully destroyed, which calls ipcomp_destroy() to delete the IPPROTO_IPIP
xfrm_state. However, by this time, the hash tables (net->xfrm.state_byxxx)
have already been kfreed in xfrm_state_fini(), leading to a use-after-free
during the deletion.
The bug has existed since kernel v2.6.29, so the patch should be
backported to all LTS kernels.
thanks,
Slavin Liu
Hi,
After a stable kernel update, the hwclock command seems no longer
functional on my SPARC system with an ST M48T59Y-70PC1 RTC:
# hwclock
[...long delay...]
hwclock: select() to /dev/rtc0 to wait for clock tick timed out
On prior kernels, there is no problem:
# hwclock
2025-10-22 22:21:04.806992-04:00
I reproduced the same failure on 6.18-rc2 and bisected to this commit:
commit 795cda8338eab036013314dbc0b04aae728880ab
Author: Esben Haabendal <esben(a)geanix.com>
Date: Fri May 16 09:23:35 2025 +0200
rtc: interface: Fix long-standing race when setting alarm
This commit was backported to all current 6.x stable branches,
as well as 5.15.x, so they all have the same regression.
Reverting this commit on top of 6.18-rc2 corrects the problem.
Let me know if you need any more info!
Thanks,
Nick