August 2025 - Linux-stable-mirror

[PATCH 0/5] drm/i915: fixes for i915 Hot Plug Detection and build/runtime issues

by Nicusor Huhulea

Hello maintainers, This series addresses a defect observed on certain hardware platforms using Linux kernel 6.1.147 with the i915 driver. The issue concerns hot plug detection (HPD) logic, leading to unreliable or missed detection events on affected hardware. This is happening on some specific devices. ### Background Issue: On Simatic IPC227E, we observed unreliable or missing hot plug detection events, while on Simatic IPC227G (otherwise similar platform), expected hot plug behavior was maintained. Affected kernel: This patch series is intended for the Linux 6.1.y stable tree only (tested on 6.1.147) Most of the tests were conducted on 6.1.147 (manual/standalone kernel build, CIP/Isar context). Root cause analysis: I do not have access to hardware signal traces or scope data to conclusively prove the root cause at electrical level. My understanding is based on observed driver behavior and logs. Therefore my assumption as to the real cause is that on IPC227G, HPD IRQ storms are apparently not occurring, so the standard HPD IRQ-based detection works as expected. On IPC227E, frequent HPD interrupts trigger the i915 driver’s storm detection logic, causing it to switch to polling mode. Therefore polling does not resume correctly, leading to the hotplug issue this series addresses. Device IPC227E's behavior triggers this kernel edge case, likely due to slight variations in signal integrity, electrical margins, or internal component timing. Device IPC227G, functions as expected, possibly due to cleaner electrical signaling or more optimal timing characteristics, thus avoiding the triggering condition. Conclusion: This points to a hardware-software interaction where kernel code assumes nicer signaling or margins than IPC227E is able to provide, exposing logic gaps not visible on more robust hardware. ### Patches Patches 1-4: - Partial backports of upstream commits; only the relevant logic or fixes are applied, with other code omitted due to downstream divergence. - Applied minimal merging without exhaustive backport of all intermediate upstream changes. Patch 5: - Contains cherry-picked logic plus context/compatibility amendments as needed. Ensures that the driver builds. - Together these fixes greatly improve reliability of hotplug detection on both devices, with no regression detected in our setups. Thank you for your review, Nicusor Huhulea This patch series contains the following changes: Dmitry Baryshkov (2): drm/probe_helper: extract two helper functions drm/probe-helper: enable and disable HPD on connectors Imre Deak (2): drm/i915: Fix HPD polling, reenabling the output poll work as needed drm: Add an HPD poll helper to reschedule the poll work Nicusor Huhulea (1): drm/i915: fixes for i915 Hot Plug Detection and build/runtime issues drivers/gpu/drm/drm_probe_helper.c | 127 ++++++++++++++----- drivers/gpu/drm/i915/display/intel_hotplug.c | 4 +- include/drm/drm_modeset_helper_vtables.h | 22 ++++ include/drm/drm_probe_helper.h | 1 + 4 files changed, 122 insertions(+), 32 deletions(-) -- 2.39.2

2 hours, 47 minutes

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[PATCH 0/4] i2c: rtl9300: Fix multi-byte I2C operations

by Sven Eckelmann

During the integration of the RTL8239 POE chip + its frontend MCU, it was noticed that multi-byte operations were basically broken in the current driver. Tests using SMBus Block Writes showed that the data (after the Wr + Ack marker) was mixed up on the wire. At first glance, it looked like an endianness problem. But for transfers were the number of count + data bytes was not divisible by 4, the last bytes were not looking like an endianness problem because they were were in the wrong order but not for example 0 - which would be the case for an endianness problem with 32 bit registers. At the end, it turned out to be a the way how i2c_write tried to add the bytes to the send registers. Each 32 bit register was used similar to a shift register - shifting the various bytes up the register while the next one is added to the least significant byte. But the I2C controller expects the first byte of the tranmission in the least significant byte of the first register. And the last byte (assuming it is a 16 byte transfer) in the most significant byte of the fourth register. While doing these tests, it was also observed that the count byte was missing from the SMBus Block Writes. The driver just removed them from the data->block (from the I2C subsystem). But the I2C controller DOES NOT automatically add this byte - for example by using the configured transmission length. The RTL8239 MCU is not actually an SMBus compliant device. Instead, it expects I2C Block Reads + I2C Block Writes. But according to the already identified bugs in the driver, it was clear that the I2C controller can simply be modified to not send the count byte for I2C_SMBUS_I2C_BLOCK_DATA. The receive part, just needs to write the content of the receive buffer to the correct position in data->block. While the on-wire formwat was now correct, reads were still not possible against the MCU (for the RTL8239 POE chip). It was always timing out because the 2ms were not enough for sending the read request and then receiving the 12 byte answer. These changes were originally submitted to OpenWrt. But there are plans to migrate OpenWrt to the upstream Linux driver. As result, the pull request was stopped and the changes were redone against this driver. Signed-off-by: Sven Eckelmann <sven(a)narfation.org> --- Harshal Gohel (2): i2c: rtl9300: Fix multi-byte I2C write i2c: rtl9300: Implement I2C block read and write Sven Eckelmann (2): i2c: rtl9300: Increase timeout for transfer polling i2c: rtl9300: Add missing count byte for SMBus Block Write drivers/i2c/busses/i2c-rtl9300.c | 43 +++++++++++++++++++++++++++++++++------- 1 file changed, 36 insertions(+), 7 deletions(-) --- base-commit: b9ddaa95fd283bce7041550ddbbe7e764c477110 change-id: 20250802-i2c-rtl9300-multi-byte-edaa1fb0872c Best regards, -- Sven Eckelmann <sven(a)narfation.org>

3 hours, 24 minutes

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[PATCH] firmware: meson_sm: fix device leak at probe

by Johan Hovold

Make sure to drop the reference to the secure monitor device taken by of_find_device_by_node() when looking up its driver data on behalf of other drivers (e.g. during probe). Note that holding a reference to the platform device does not prevent its driver data from going away so there is no point in keeping the reference after the helper returns. Fixes: 8cde3c2153e8 ("firmware: meson_sm: Rework driver as a proper platform driver") Cc: stable(a)vger.kernel.org # 5.5 Cc: Carlo Caione <ccaione(a)baylibre.com> Signed-off-by: Johan Hovold <johan(a)kernel.org> --- drivers/firmware/meson/meson_sm.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c index f25a9746249b..3ab67aaa9e5d 100644 --- a/drivers/firmware/meson/meson_sm.c +++ b/drivers/firmware/meson/meson_sm.c @@ -232,11 +232,16 @@ EXPORT_SYMBOL(meson_sm_call_write); struct meson_sm_firmware *meson_sm_get(struct device_node *sm_node) { struct platform_device *pdev = of_find_device_by_node(sm_node); + struct meson_sm_firmware *fw; if (!pdev) return NULL; - return platform_get_drvdata(pdev); + fw = platform_get_drvdata(pdev); + + put_device(&pdev->dev); + + return fw; } EXPORT_SYMBOL_GPL(meson_sm_get); -- 2.49.1

4 hours, 12 minutes

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[PATCH vulns 0/1] change the sha1 for CVE-2024-26661

by Qingfeng Hao

There is a fix 17ba9cde11c2bfebbd70867b0a2ac4a22e573379 introduced in v6.8 to fix the problem introduced by the original fix 66951d98d9bf45ba25acf37fe0747253fafdf298, and they together fix the CVE-2024-26661. Since this is the first time I submit the changes on vulns project, not sure if the changes in my patch are exact, @Greg, please point out the problems if there are and I will fix them. Thanks! Qingfeng Hao (1): CVE-2024-26661: change the sha1 of the cve id cve/published/2024/CVE-2024-26661.dyad | 6 ++-- cve/published/2024/CVE-2024-26661.json | 46 ++------------------------ cve/published/2024/CVE-2024-26661.sha1 | 2 +- 3 files changed, 5 insertions(+), 49 deletions(-) -- 2.34.1

5 hours, 55 minutes

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[PATCH] mm: Fix possible deadlock in console_trylock_spinning

by Gu Bowen

kmemleak_scan_thread() invokes scan_block() which may invoke a nomal printk() to print warning message. This can cause a deadlock in the scenario reported below: CPU0 CPU1 ---- ---- lock(kmemleak_lock); lock(&port->lock); lock(kmemleak_lock); lock(console_owner); To solve this problem, switch to printk_safe mode before printing warning message, this will redirect all printk()-s to a special per-CPU buffer, which will be flushed later from a safe context (irq work), and this deadlock problem can be avoided. Our syztester report the following lockdep error: ====================================================== WARNING: possible circular locking dependency detected 5.10.0-22221-gca646a51dd00 #16 Not tainted ------------------------------------------------------ kmemleak/182 is trying to acquire lock: ffffffffaf9e9020 (console_owner){-...}-{0:0}, at: console_trylock_spinning+0xda/0x1d0 kernel/printk/printk.c:1900 but task is already holding lock: ffffffffb007cf58 (kmemleak_lock){-.-.}-{2:2}, at: scan_block+0x3d/0x220 mm/kmemleak.c:1310 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (kmemleak_lock){-.-.}-{2:2}: validate_chain+0x5df/0xac0 kernel/locking/lockdep.c:3729 __lock_acquire+0x514/0x940 kernel/locking/lockdep.c:4958 lock_acquire+0x15a/0x3a0 kernel/locking/lockdep.c:5569 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3b/0x60 kernel/locking/spinlock.c:164 create_object.isra.0+0x36/0x80 mm/kmemleak.c:691 kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline] slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc_node mm/slub.c:2987 [inline] slab_alloc mm/slub.c:2995 [inline] __kmalloc+0x637/0xb60 mm/slub.c:4100 kmalloc include/linux/slab.h:620 [inline] tty_buffer_alloc+0x127/0x140 drivers/tty/tty_buffer.c:176 __tty_buffer_request_room+0x9b/0x110 drivers/tty/tty_buffer.c:276 tty_insert_flip_string_fixed_flag+0x60/0x130 drivers/tty/tty_buffer.c:321 tty_insert_flip_string include/linux/tty_flip.h:36 [inline] tty_insert_flip_string_and_push_buffer+0x3a/0xb0 drivers/tty/tty_buffer.c:578 process_output_block+0xc2/0x2e0 drivers/tty/n_tty.c:592 n_tty_write+0x298/0x540 drivers/tty/n_tty.c:2433 do_tty_write drivers/tty/tty_io.c:1041 [inline] file_tty_write.constprop.0+0x29b/0x4b0 drivers/tty/tty_io.c:1147 redirected_tty_write+0x51/0x90 drivers/tty/tty_io.c:1176 call_write_iter include/linux/fs.h:2117 [inline] do_iter_readv_writev+0x274/0x350 fs/read_write.c:741 do_iter_write+0xbb/0x1f0 fs/read_write.c:867 vfs_writev+0xfa/0x380 fs/read_write.c:940 do_writev+0xd6/0x1d0 fs/read_write.c:983 do_syscall_64+0x2b/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x6c/0xd6 -> #2 (&port->lock){-.-.}-{2:2}: validate_chain+0x5df/0xac0 kernel/locking/lockdep.c:3729 __lock_acquire+0x514/0x940 kernel/locking/lockdep.c:4958 lock_acquire+0x15a/0x3a0 kernel/locking/lockdep.c:5569 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3b/0x60 kernel/locking/spinlock.c:164 tty_port_tty_get+0x1f/0xa0 drivers/tty/tty_port.c:289 tty_port_default_wakeup+0xb/0x30 drivers/tty/tty_port.c:48 serial8250_tx_chars+0x259/0x430 drivers/tty/serial/8250/8250_port.c:1906 __start_tx drivers/tty/serial/8250/8250_port.c:1598 [inline] serial8250_start_tx+0x304/0x320 drivers/tty/serial/8250/8250_port.c:1720 uart_write+0x1a1/0x2e0 drivers/tty/serial/serial_core.c:635 do_output_char+0x2c0/0x370 drivers/tty/n_tty.c:444 process_output drivers/tty/n_tty.c:511 [inline] n_tty_write+0x269/0x540 drivers/tty/n_tty.c:2445 do_tty_write drivers/tty/tty_io.c:1041 [inline] file_tty_write.constprop.0+0x29b/0x4b0 drivers/tty/tty_io.c:1147 call_write_iter include/linux/fs.h:2117 [inline] do_iter_readv_writev+0x274/0x350 fs/read_write.c:741 do_iter_write+0xbb/0x1f0 fs/read_write.c:867 vfs_writev+0xfa/0x380 fs/read_write.c:940 do_writev+0xd6/0x1d0 fs/read_write.c:983 do_syscall_64+0x2b/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x6c/0xd6 -> #1 (&port_lock_key){-.-.}-{2:2}: validate_chain+0x5df/0xac0 kernel/locking/lockdep.c:3729 __lock_acquire+0x514/0x940 kernel/locking/lockdep.c:4958 lock_acquire+0x15a/0x3a0 kernel/locking/lockdep.c:5569 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3b/0x60 kernel/locking/spinlock.c:164 serial8250_console_write+0x292/0x320 drivers/tty/serial/8250/8250_port.c:3458 call_console_drivers.constprop.0+0x185/0x240 kernel/printk/printk.c:1988 console_unlock+0x2b4/0x640 kernel/printk/printk.c:2648 register_console.part.0+0x2a1/0x390 kernel/printk/printk.c:3024 univ8250_console_init+0x24/0x2b drivers/tty/serial/8250/8250_core.c:724 console_init+0x188/0x24b kernel/printk/printk.c:3134 start_kernel+0x2b0/0x41e init/main.c:1072 secondary_startup_64_no_verify+0xc3/0xcb -> #0 (console_owner){-...}-{0:0}: check_prev_add+0xfa/0x1380 kernel/locking/lockdep.c:2988 check_prevs_add+0x1d8/0x3c0 kernel/locking/lockdep.c:3113 validate_chain+0x5df/0xac0 kernel/locking/lockdep.c:3729 __lock_acquire+0x514/0x940 kernel/locking/lockdep.c:4958 lock_acquire+0x15a/0x3a0 kernel/locking/lockdep.c:5569 console_trylock_spinning+0x10d/0x1d0 kernel/printk/printk.c:1921 vprintk_emit+0x1a5/0x270 kernel/printk/printk.c:2134 printk+0xb2/0xe7 kernel/printk/printk.c:2183 lookup_object.cold+0xf/0x24 mm/kmemleak.c:405 scan_block+0x1fa/0x220 mm/kmemleak.c:1357 scan_object+0xdd/0x140 mm/kmemleak.c:1415 scan_gray_list+0x8f/0x1c0 mm/kmemleak.c:1453 kmemleak_scan+0x649/0xf30 mm/kmemleak.c:1608 kmemleak_scan_thread+0x94/0xb6 mm/kmemleak.c:1721 kthread+0x1c4/0x210 kernel/kthread.c:328 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:299 other info that might help us debug this: Chain exists of: console_owner --> &port->lock --> kmemleak_lock Cc: stable(a)vger.kernel.org # 5.10 Signed-off-by: Gu Bowen <gubowen5(a)huawei.com> --- mm/kmemleak.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 4801751cb6b6..d322897a1de1 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -390,9 +390,11 @@ static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) else if (object->pointer == ptr || alias) return object; else { + __printk_safe_enter(); kmemleak_warn("Found object by alias at 0x%08lx\n", ptr); dump_object_info(object); + __printk_safe_exit(); break; } } -- 2.25.1

10 hours, 21 minutes

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[PATCH v4] Mark xe driver as BROKEN if kernel page size is not 4kB

by Simon Richter

This driver, for the time being, assumes that the kernel page size is 4kB, so it fails on loong64 and aarch64 with 16kB pages, and ppc64el with 64kB pages. Signed-off-by: Simon Richter <Simon.Richter(a)hogyros.de> Cc: stable(a)vger.kernel.org --- drivers/gpu/drm/xe/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/xe/Kconfig b/drivers/gpu/drm/xe/Kconfig index 2bb2bc052120..714d5702dfd7 100644 --- a/drivers/gpu/drm/xe/Kconfig +++ b/drivers/gpu/drm/xe/Kconfig @@ -5,6 +5,7 @@ config DRM_XE depends on KUNIT || !KUNIT depends on INTEL_VSEC || !INTEL_VSEC depends on X86_PLATFORM_DEVICES || !(X86 && ACPI) + depends on PAGE_SIZE_4KB || COMPILE_TEST || BROKEN select INTERVAL_TREE # we need shmfs for the swappable backing store, and in particular # the shmem_readpage() which depends upon tmpfs -- 2.47.2

11 hours, 34 minutes

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[PATCH v2 1/1] userfaultfd: fix a crash when UFFDIO_MOVE handles a THP hole

by Suren Baghdasaryan

When UFFDIO_MOVE is used with UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES and it encounters a non-present THP, it fails to properly recognize an unmapped hole and tries to access a non-existent folio, resulting in a crash. Add a check to skip non-present THPs. Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI") Reported-by: syzbot+b446dbe27035ef6bd6c2(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68794b5c.a70a0220.693ce.0050.GAE@google.com/ Signed-off-by: Suren Baghdasaryan <surenb(a)google.com> Cc: stable(a)vger.kernel.org --- Changes since v1 [1] - Fixed step size calculation, per Lokesh Gidra - Added missing check for UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES, per Lokesh Gidra [1] https://lore.kernel.org/all/20250730170733.3829267-1-surenb@google.com/ mm/userfaultfd.c | 45 +++++++++++++++++++++++++++++---------------- 1 file changed, 29 insertions(+), 16 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index cbed91b09640..b5af31c22731 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -1818,28 +1818,41 @@ ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start, ptl = pmd_trans_huge_lock(src_pmd, src_vma); if (ptl) { - /* Check if we can move the pmd without splitting it. */ - if (move_splits_huge_pmd(dst_addr, src_addr, src_start + len) || - !pmd_none(dst_pmdval)) { - struct folio *folio = pmd_folio(*src_pmd); + if (pmd_present(*src_pmd) || is_pmd_migration_entry(*src_pmd)) { + /* Check if we can move the pmd without splitting it. */ + if (move_splits_huge_pmd(dst_addr, src_addr, src_start + len) || + !pmd_none(dst_pmdval)) { + if (pmd_present(*src_pmd)) { + struct folio *folio = pmd_folio(*src_pmd); + + if (!folio || (!is_huge_zero_folio(folio) && + !PageAnonExclusive(&folio->page))) { + spin_unlock(ptl); + err = -EBUSY; + break; + } + } - if (!folio || (!is_huge_zero_folio(folio) && - !PageAnonExclusive(&folio->page))) { spin_unlock(ptl); - err = -EBUSY; - break; + split_huge_pmd(src_vma, src_pmd, src_addr); + /* The folio will be split by move_pages_pte() */ + continue; } + err = move_pages_huge_pmd(mm, dst_pmd, src_pmd, + dst_pmdval, dst_vma, src_vma, + dst_addr, src_addr); + step_size = HPAGE_PMD_SIZE; + } else { spin_unlock(ptl); - split_huge_pmd(src_vma, src_pmd, src_addr); - /* The folio will be split by move_pages_pte() */ - continue; + if (!(mode & UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES)) { + err = -ENOENT; + break; + } + /* nothing to do to move a hole */ + err = 0; + step_size = min(HPAGE_PMD_SIZE, src_start + len - src_addr); } - - err = move_pages_huge_pmd(mm, dst_pmd, src_pmd, - dst_pmdval, dst_vma, src_vma, - dst_addr, src_addr); - step_size = HPAGE_PMD_SIZE; } else { if (pmd_none(*src_pmd)) { if (!(mode & UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES)) { base-commit: 01da54f10fddf3b01c5a3b80f6b16bbad390c302 -- 2.50.1.552.g942d659e1b-goog

13 hours, 42 minutes

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+ mm-fix-possible-deadlock-in-console_trylock_spinning.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm: fix possible deadlock in console_trylock_spinning has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-fix-possible-deadlock-in-console_trylock_spinning.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Gu Bowen <gubowen5(a)huawei.com> Subject: mm: fix possible deadlock in console_trylock_spinning Date: Wed, 30 Jul 2025 17:49:14 +0800 kmemleak_scan_thread() invokes scan_block() which may invoke a nomal printk() to print warning message. This can cause a deadlock in the scenario reported below: CPU0 CPU1 ---- ---- lock(kmemleak_lock); lock(&port->lock); lock(kmemleak_lock); lock(console_owner); To solve this problem, switch to printk_safe mode before printing warning message, this will redirect all printk()-s to a special per-CPU buffer, which will be flushed later from a safe context (irq work), and this deadlock problem can be avoided. Our syztester report the following lockdep error: ====================================================== WARNING: possible circular locking dependency detected 5.10.0-22221-gca646a51dd00 #16 Not tainted ------------------------------------------------------ kmemleak/182 is trying to acquire lock: ffffffffaf9e9020 (console_owner){-...}-{0:0}, at: console_trylock_spinning+0xda/0x1d0 kernel/printk/printk.c:1900 but task is already holding lock: ffffffffb007cf58 (kmemleak_lock){-.-.}-{2:2}, at: scan_block+0x3d/0x220 mm/kmemleak.c:1310 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (kmemleak_lock){-.-.}-{2:2}: validate_chain+0x5df/0xac0 kernel/locking/lockdep.c:3729 __lock_acquire+0x514/0x940 kernel/locking/lockdep.c:4958 lock_acquire+0x15a/0x3a0 kernel/locking/lockdep.c:5569 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3b/0x60 kernel/locking/spinlock.c:164 create_object.isra.0+0x36/0x80 mm/kmemleak.c:691 kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline] slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc_node mm/slub.c:2987 [inline] slab_alloc mm/slub.c:2995 [inline] __kmalloc+0x637/0xb60 mm/slub.c:4100 kmalloc include/linux/slab.h:620 [inline] tty_buffer_alloc+0x127/0x140 drivers/tty/tty_buffer.c:176 __tty_buffer_request_room+0x9b/0x110 drivers/tty/tty_buffer.c:276 tty_insert_flip_string_fixed_flag+0x60/0x130 drivers/tty/tty_buffer.c:321 tty_insert_flip_string include/linux/tty_flip.h:36 [inline] tty_insert_flip_string_and_push_buffer+0x3a/0xb0 drivers/tty/tty_buffer.c:578 process_output_block+0xc2/0x2e0 drivers/tty/n_tty.c:592 n_tty_write+0x298/0x540 drivers/tty/n_tty.c:2433 do_tty_write drivers/tty/tty_io.c:1041 [inline] file_tty_write.constprop.0+0x29b/0x4b0 drivers/tty/tty_io.c:1147 redirected_tty_write+0x51/0x90 drivers/tty/tty_io.c:1176 call_write_iter include/linux/fs.h:2117 [inline] do_iter_readv_writev+0x274/0x350 fs/read_write.c:741 do_iter_write+0xbb/0x1f0 fs/read_write.c:867 vfs_writev+0xfa/0x380 fs/read_write.c:940 do_writev+0xd6/0x1d0 fs/read_write.c:983 do_syscall_64+0x2b/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x6c/0xd6 -> #2 (&port->lock){-.-.}-{2:2}: validate_chain+0x5df/0xac0 kernel/locking/lockdep.c:3729 __lock_acquire+0x514/0x940 kernel/locking/lockdep.c:4958 lock_acquire+0x15a/0x3a0 kernel/locking/lockdep.c:5569 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3b/0x60 kernel/locking/spinlock.c:164 tty_port_tty_get+0x1f/0xa0 drivers/tty/tty_port.c:289 tty_port_default_wakeup+0xb/0x30 drivers/tty/tty_port.c:48 serial8250_tx_chars+0x259/0x430 drivers/tty/serial/8250/8250_port.c:1906 __start_tx drivers/tty/serial/8250/8250_port.c:1598 [inline] serial8250_start_tx+0x304/0x320 drivers/tty/serial/8250/8250_port.c:1720 uart_write+0x1a1/0x2e0 drivers/tty/serial/serial_core.c:635 do_output_char+0x2c0/0x370 drivers/tty/n_tty.c:444 process_output drivers/tty/n_tty.c:511 [inline] n_tty_write+0x269/0x540 drivers/tty/n_tty.c:2445 do_tty_write drivers/tty/tty_io.c:1041 [inline] file_tty_write.constprop.0+0x29b/0x4b0 drivers/tty/tty_io.c:1147 call_write_iter include/linux/fs.h:2117 [inline] do_iter_readv_writev+0x274/0x350 fs/read_write.c:741 do_iter_write+0xbb/0x1f0 fs/read_write.c:867 vfs_writev+0xfa/0x380 fs/read_write.c:940 do_writev+0xd6/0x1d0 fs/read_write.c:983 do_syscall_64+0x2b/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x6c/0xd6 -> #1 (&port_lock_key){-.-.}-{2:2}: validate_chain+0x5df/0xac0 kernel/locking/lockdep.c:3729 __lock_acquire+0x514/0x940 kernel/locking/lockdep.c:4958 lock_acquire+0x15a/0x3a0 kernel/locking/lockdep.c:5569 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3b/0x60 kernel/locking/spinlock.c:164 serial8250_console_write+0x292/0x320 drivers/tty/serial/8250/8250_port.c:3458 call_console_drivers.constprop.0+0x185/0x240 kernel/printk/printk.c:1988 console_unlock+0x2b4/0x640 kernel/printk/printk.c:2648 register_console.part.0+0x2a1/0x390 kernel/printk/printk.c:3024 univ8250_console_init+0x24/0x2b drivers/tty/serial/8250/8250_core.c:724 console_init+0x188/0x24b kernel/printk/printk.c:3134 start_kernel+0x2b0/0x41e init/main.c:1072 secondary_startup_64_no_verify+0xc3/0xcb -> #0 (console_owner){-...}-{0:0}: check_prev_add+0xfa/0x1380 kernel/locking/lockdep.c:2988 check_prevs_add+0x1d8/0x3c0 kernel/locking/lockdep.c:3113 validate_chain+0x5df/0xac0 kernel/locking/lockdep.c:3729 __lock_acquire+0x514/0x940 kernel/locking/lockdep.c:4958 lock_acquire+0x15a/0x3a0 kernel/locking/lockdep.c:5569 console_trylock_spinning+0x10d/0x1d0 kernel/printk/printk.c:1921 vprintk_emit+0x1a5/0x270 kernel/printk/printk.c:2134 printk+0xb2/0xe7 kernel/printk/printk.c:2183 lookup_object.cold+0xf/0x24 mm/kmemleak.c:405 scan_block+0x1fa/0x220 mm/kmemleak.c:1357 scan_object+0xdd/0x140 mm/kmemleak.c:1415 scan_gray_list+0x8f/0x1c0 mm/kmemleak.c:1453 kmemleak_scan+0x649/0xf30 mm/kmemleak.c:1608 kmemleak_scan_thread+0x94/0xb6 mm/kmemleak.c:1721 kthread+0x1c4/0x210 kernel/kthread.c:328 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:299 other info that might help us debug this: Chain exists of: console_owner --> &port->lock --> kmemleak_lock Link: https://lkml.kernel.org/r/20250730094914.566582-1-gubowen5@huawei.com Signed-off-by: Gu Bowen <gubowen5(a)huawei.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Lu Jialin <lujialin4(a)huawei.com> Cc: Waiman Long <longman(a)redhat.com> Cc: Breno Leitao <leitao(a)debian.org> Cc: <stable(a)vger.kernel.org> [5.10+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/kmemleak.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/kmemleak.c~mm-fix-possible-deadlock-in-console_trylock_spinning +++ a/mm/kmemleak.c @@ -437,9 +437,11 @@ static struct kmemleak_object *__lookup_ else if (untagged_objp == untagged_ptr || alias) return object; else { + __printk_safe_enter(); kmemleak_warn("Found object by alias at 0x%08lx\n", ptr); dump_object_info(object); + __printk_safe_exit(); break; } } _ Patches currently in -mm which might be from gubowen5(a)huawei.com are mm-fix-possible-deadlock-in-console_trylock_spinning.patch

15 hours, 40 minutes

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[PATCH] kcov, usb: Fix invalid context sleep in softirq path on PREEMPT_RT

by Yunseong Kim

When fuzzing USB with syzkaller on a PREEMPT_RT enabled kernel, following bug is triggered in the ksoftirqd context. | BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 | in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 30, name: ksoftirqd/1 | preempt_count: 0, expected: 0 | RCU nest depth: 2, expected: 2 | CPU: 1 UID: 0 PID: 30 Comm: ksoftirqd/1 Tainted: G W 6.16.0-rc1-rt1 #11 PREEMPT_RT | Tainted: [W]=WARN | Hardware name: QEMU KVM Virtual Machine, BIOS 2025.02-8 05/13/2025 | Call trace: | show_stack+0x2c/0x3c (C) | __dump_stack+0x30/0x40 | dump_stack_lvl+0x148/0x1d8 | dump_stack+0x1c/0x3c | __might_resched+0x2e4/0x52c | rt_spin_lock+0xa8/0x1bc | kcov_remote_start+0xb0/0x490 | __usb_hcd_giveback_urb+0x2d0/0x5e8 | usb_giveback_urb_bh+0x234/0x3c4 | process_scheduled_works+0x678/0xd18 | bh_worker+0x2f0/0x59c | workqueue_softirq_action+0x104/0x14c | tasklet_action+0x18/0x8c | handle_softirqs+0x208/0x63c | run_ksoftirqd+0x64/0x264 | smpboot_thread_fn+0x4ac/0x908 | kthread+0x5e8/0x734 | ret_from_fork+0x10/0x20 To reproduce on PREEMPT_RT kernel: $ git remote add rt-devel git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git $ git fetch rt-devel $ git checkout -b v6.16-rc1-rt1 v6.16-rc1-rt1 I have attached the syzlang and the C source code converted by syz-prog2c: Link: https://gist.github.com/kzall0c/9455aaa246f4aa1135353a51753adbbe Then, run with a PREEMPT_RT config. This issue was introduced by commit f85d39dd7ed8 ("kcov, usb: disable interrupts in kcov_remote_start_usb_softirq"). However, this creates a conflict on PREEMPT_RT kernels. The local_irq_save() call establishes an atomic context where sleeping is forbidden. Inside this context, kcov_remote_start() is called, which on PREEMPT_RT uses sleeping locks (spinlock_t and local_lock_t are mapped to rt_mutex). This results in a sleeping function called from invalid context. On PREEMPT_RT, interrupt handlers are threaded, so the re-entrancy scenario is already safely handled by the existing local_lock_t and the global kcov_remote_lock within kcov_remote_start(). Therefore, the outer local_irq_save() is not necessary. This preserves the intended re-entrancy protection for non-RT kernels while resolving the locking violation on PREEMPT_RT kernels. After making this modification and testing it, syzkaller fuzzing the PREEMPT_RT kernel is now running without stopping on latest announced Real-time Linux. Link: https://lore.kernel.org/linux-rt-devel/20250610080307.LMm1hleC@linutronix.d… Fixes: f85d39dd7ed8 ("kcov, usb: disable interrupts in kcov_remote_start_usb_softirq") Cc: Andrey Konovalov <andreyknvl(a)gmail.com> Cc: Tetsuo Handa <penguin-kernel(a)i-love.sakura.ne.jp> Cc: Alan Stern <stern(a)rowland.harvard.edu> Cc: Dmitry Vyukov <dvyukov(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> Cc: Byungchul Park <byungchul(a)sk.com> Cc: stable(a)vger.kernel.org Cc: kasan-dev(a)googlegroups.com Cc: syzkaller(a)googlegroups.com Cc: linux-usb(a)vger.kernel.org Cc: linux-rt-devel(a)lists.linux.dev Signed-off-by: Yunseong Kim <ysk(a)kzalloc.com> --- include/linux/kcov.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/kcov.h b/include/linux/kcov.h index 75a2fb8b16c3..c5e1b2dd0bb7 100644 --- a/include/linux/kcov.h +++ b/include/linux/kcov.h @@ -85,7 +85,9 @@ static inline unsigned long kcov_remote_start_usb_softirq(u64 id) unsigned long flags = 0; if (in_serving_softirq()) { +#ifndef CONFIG_PREEMPT_RT local_irq_save(flags); +#endif kcov_remote_start_usb(id); } @@ -96,7 +98,9 @@ static inline void kcov_remote_stop_softirq(unsigned long flags) { if (in_serving_softirq()) { kcov_remote_stop(); +#ifndef CONFIG_PREEMPT_RT local_irq_restore(flags); +#endif } } -- 2.50.0

16 hours, 8 minutes

4
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[PATCH] fs: correctly check for errors from replace_fd() in receive_fd_replace()

by Thomas Weißschuh

replace_fd() returns either a negative error number or the number of the new file descriptor. The current code misinterprets any positive file descriptor number as an error. Only check for negative error numbers, so that __receive_sock() is called correctly for valid file descriptors. Fixes: 173817151b15 ("fs: Expand __receive_fd() to accept existing fd") Fixes: 42eb0d54c08a ("fs: split receive_fd_replace from __receive_fd") Cc: stable(a)vger.kernel.org Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- Untested, it stuck out while reading the code. --- fs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/file.c b/fs/file.c index 6d2275c3be9c6967d16c75d1b6521f9b58980926..56c3a045121d8f43a54cf05e6ce1962f896339ac 100644 --- a/fs/file.c +++ b/fs/file.c @@ -1387,7 +1387,7 @@ int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags) if (error) return error; error = replace_fd(new_fd, file, o_flags); - if (error) + if (error < 0) return error; __receive_sock(file); return new_fd; --- base-commit: 89748acdf226fd1a8775ff6fa2703f8412b286c8 change-id: 20250801-fix-receive_fd_replace-7fdd5ce6532d Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

16 hours, 12 minutes

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