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[PATCH] shmem: fix tmpfs reconfiguration (remount) when noswap is set

by Mike Yuan

In systemd we're trying to switch the internal credentials setup logic to new mount API [1], and I noticed fsconfig(FSCONFIG_CMD_RECONFIGURE) consistently fails on tmpfs with noswap option. This can be trivially reproduced with the following: ``` int fs_fd = fsopen("tmpfs", 0); fsconfig(fs_fd, FSCONFIG_SET_FLAG, "noswap", NULL, 0); fsconfig(fs_fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0); fsmount(fs_fd, 0, 0); fsconfig(fs_fd, FSCONFIG_CMD_RECONFIGURE, NULL, NULL, 0); <------ EINVAL ``` After some digging the culprit is shmem_reconfigure() rejecting !(ctx->seen & SHMEM_SEEN_NOSWAP) && sbinfo->noswap, which is bogus as ctx->seen serves as a mask for whether certain options are touched at all. On top of that, noswap option doesn't use fsparam_flag_no, hence it's not really possible to "reenable" swap to begin with. Drop the check and redundant SHMEM_SEEN_NOSWAP flag. [1] https://github.com/systemd/systemd/pull/39637 Fixes: 2c6efe9cf2d7 ("shmem: add support to ignore swap") Signed-off-by: Mike Yuan <me(a)yhndnzj.com> Cc: Luis Chamberlain <mcgrof(a)kernel.org> Cc: Christian Brauner <brauner(a)kernel.org> Cc: Hugh Dickins <hughd(a)google.com> Cc: <stable(a)vger.kernel.org> --- mm/shmem.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index b9081b817d28..1b976414d6fa 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -131,8 +131,7 @@ struct shmem_options { #define SHMEM_SEEN_INODES 2 #define SHMEM_SEEN_HUGE 4 #define SHMEM_SEEN_INUMS 8 -#define SHMEM_SEEN_NOSWAP 16 -#define SHMEM_SEEN_QUOTA 32 +#define SHMEM_SEEN_QUOTA 16 }; #ifdef CONFIG_TRANSPARENT_HUGEPAGE @@ -4677,7 +4676,6 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param) "Turning off swap in unprivileged tmpfs mounts unsupported"); } ctx->noswap = true; - ctx->seen |= SHMEM_SEEN_NOSWAP; break; case Opt_quota: if (fc->user_ns != &init_user_ns) @@ -4827,14 +4825,15 @@ static int shmem_reconfigure(struct fs_context *fc) err = "Current inum too high to switch to 32-bit inums"; goto out; } - if ((ctx->seen & SHMEM_SEEN_NOSWAP) && ctx->noswap && !sbinfo->noswap) { + + /* + * "noswap" doesn't use fsparam_flag_no, i.e. there's no "swap" + * counterpart for (re-)enabling swap. + */ + if (ctx->noswap && !sbinfo->noswap) { err = "Cannot disable swap on remount"; goto out; } - if (!(ctx->seen & SHMEM_SEEN_NOSWAP) && !ctx->noswap && sbinfo->noswap) { - err = "Cannot enable swap on remount if it was disabled on first mount"; - goto out; - } if (ctx->seen & SHMEM_SEEN_QUOTA && !sb_any_quota_loaded(fc->root->d_sb)) { base-commit: 0d7bee10beeb59b1133bf5a4749b17a4ef3bbb01 -- 2.51.1

5 days, 15 hours

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[PATCH v2] powerpc: Add reloc_offset() to font bitmap pointer used for bootx_printf()

by Finn Thain

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

5 days, 15 hours

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[PATCH] slimbus: ngd: Fix reference count leak in qcom_slim_ngd_notify_slaves

by Miaoqian Lin

The function qcom_slim_ngd_notify_slaves() calls of_slim_get_device() which internally uses device_find_child() to obtain a device reference. According to the device_find_child() documentation, the caller must drop the reference with put_device() after use. Found via static analysis and this is similar to commit 4e65bda8273c ("ASoC: wcd934x: fix error handling in wcd934x_codec_parse_data()") Fixes: 917809e2280b ("slimbus: ngd: Add qcom SLIMBus NGD driver") Cc: stable(a)vger.kernel.org Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com> --- drivers/slimbus/qcom-ngd-ctrl.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c index 4fb66986cc22..cd40ab839c54 100644 --- a/drivers/slimbus/qcom-ngd-ctrl.c +++ b/drivers/slimbus/qcom-ngd-ctrl.c @@ -1241,6 +1241,7 @@ static void qcom_slim_ngd_notify_slaves(struct qcom_slim_ngd_ctrl *ctrl) if (slim_get_logical_addr(sbdev)) dev_err(ctrl->dev, "Failed to get logical address\n"); + put_device(&sbdev->dev); } } -- 2.39.5 (Apple Git-154)

5 days, 15 hours

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[PATCH 6.12] io_uring/napi: fix io_napi_entry RCU accesses

by Stepan Artuhov

From: Olivier Langlois <olivier(a)trillion01.com> [Upstream commit 45b3941d09d13b3503309be1f023b83deaf69b4d ] correct 3 RCU structures modifications that were not using the RCU functions to make their update. Cc: Jens Axboe <axboe(a)kernel.dk> Cc: Pavel Begunkov <asml.silence(a)gmail.com> Cc: io-uring(a)vger.kernel.org Cc: linux-kernel(a)vger.kernel.org Cc: lvc-project(a)linuxtesting.org Signed-off-by: Olivier Langlois <olivier(a)trillion01.com> Link: https://lore.kernel.org/r/9f53b5169afa8c7bf3665a0b19dc2f7061173530.17288288… Signed-off-by: Jens Axboe <axboe(a)kernel.dk> [Stepan Artuhov: cherry-picked a commit] Signed-off-by: Stepan Artuhov <s.artuhov(a)tssltd.ru> --- io_uring/napi.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/io_uring/napi.c b/io_uring/napi.c index d0cf694d0172..fa959fd32042 100644 --- a/io_uring/napi.c +++ b/io_uring/napi.c @@ -81,19 +81,24 @@ void __io_napi_add(struct io_ring_ctx *ctx, struct socket *sock) } hlist_add_tail_rcu(&e->node, hash_list); - list_add_tail(&e->list, &ctx->napi_list); + list_add_tail_rcu(&e->list, &ctx->napi_list); spin_unlock(&ctx->napi_lock); } static void __io_napi_remove_stale(struct io_ring_ctx *ctx) { struct io_napi_entry *e; - unsigned int i; spin_lock(&ctx->napi_lock); - hash_for_each(ctx->napi_ht, i, e, node) { - if (time_after(jiffies, e->timeout)) { - list_del(&e->list); + /* + * list_for_each_entry_safe() is not required as long as: + * 1. list_del_rcu() does not reset the deleted node next pointer + * 2. kfree_rcu() delays the memory freeing until the next quiescent + * state + */ + list_for_each_entry(e, &ctx->napi_list, list) { + if (time_after(jiffies, READ_ONCE(e->timeout))) { + list_del_rcu(&e->list); hash_del_rcu(&e->node); kfree_rcu(e, rcu); } @@ -204,13 +209,13 @@ void io_napi_init(struct io_ring_ctx *ctx) void io_napi_free(struct io_ring_ctx *ctx) { struct io_napi_entry *e; - unsigned int i; spin_lock(&ctx->napi_lock); - hash_for_each(ctx->napi_ht, i, e, node) { + list_for_each_entry(e, &ctx->napi_list, list) { hash_del_rcu(&e->node); kfree_rcu(e, rcu); } + INIT_LIST_HEAD_RCU(&ctx->napi_list); spin_unlock(&ctx->napi_lock); } -- 2.39.5

5 days, 15 hours

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[PATCH v2] powerpc, mm: Fix mprotect on book3s 32-bit

by Dave Vasilevsky

On 32-bit book3s with hash-MMUs, tlb_flush() was a no-op. This was unnoticed because all uses until recently were for unmaps, and thus handled by __tlb_remove_tlb_entry(). After commit 4a18419f71cd ("mm/mprotect: use mmu_gather") in kernel 5.19, tlb_gather_mmu() started being used for mprotect as well. This caused mprotect to simply not work on these machines: int *ptr = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); *ptr = 1; // force HPTE to be created mprotect(ptr, 4096, PROT_READ); *ptr = 2; // should segfault, but succeeds Fixed by making tlb_flush() actually flush TLB pages. This finally agrees with the behaviour of boot3s64's tlb_flush(). Fixes: 4a18419f71cd ("mm/mprotect: use mmu_gather") Signed-off-by: Dave Vasilevsky <dave(a)vasilevsky.ca> Cc: stable(a)vger.kernel.org --- Changes in v2: - Flush entire TLB if full mm is requested. - Link to v1: https://lore.kernel.org/r/20251027-vasi-mprotect-g3-v1-1-3c5187085f9a@vasil… --- arch/powerpc/include/asm/book3s/32/tlbflush.h | 8 ++++++-- arch/powerpc/mm/book3s32/tlb.c | 9 +++++++++ 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/tlbflush.h b/arch/powerpc/include/asm/book3s/32/tlbflush.h index e43534da5207aa3b0cb3c07b78e29b833c141f3f..b8c587ad2ea954f179246a57d6e86e45e91dcfdc 100644 --- a/arch/powerpc/include/asm/book3s/32/tlbflush.h +++ b/arch/powerpc/include/asm/book3s/32/tlbflush.h @@ -11,6 +11,7 @@ void hash__flush_tlb_mm(struct mm_struct *mm); void hash__flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr); void hash__flush_range(struct mm_struct *mm, unsigned long start, unsigned long end); +void hash__flush_gather(struct mmu_gather *tlb); #ifdef CONFIG_SMP void _tlbie(unsigned long address); @@ -28,9 +29,12 @@ void _tlbia(void); */ static inline void tlb_flush(struct mmu_gather *tlb) { - /* 603 needs to flush the whole TLB here since it doesn't use a hash table. */ - if (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) + if (mmu_has_feature(MMU_FTR_HPTE_TABLE)) { + hash__flush_gather(tlb); + } else { + /* 603 needs to flush the whole TLB here since it doesn't use a hash table. */ _tlbia(); + } } static inline void flush_range(struct mm_struct *mm, unsigned long start, unsigned long end) diff --git a/arch/powerpc/mm/book3s32/tlb.c b/arch/powerpc/mm/book3s32/tlb.c index 9ad6b56bfec96e989b96f027d075ad5812500854..e54a7b0112322e5818d80facd2e3c7722e6dd520 100644 --- a/arch/powerpc/mm/book3s32/tlb.c +++ b/arch/powerpc/mm/book3s32/tlb.c @@ -105,3 +105,12 @@ void hash__flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr) flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1); } EXPORT_SYMBOL(hash__flush_tlb_page); + +void hash__flush_gather(struct mmu_gather *tlb) +{ + if (tlb->fullmm || tlb->need_flush_all) + hash__flush_tlb_mm(tlb->mm); + else + hash__flush_range(tlb->mm, tlb->start, tlb->end); +} +EXPORT_SYMBOL(hash__flush_gather); --- base-commit: 24172e0d79900908cf5ebf366600616d29c9b417 change-id: 20251027-vasi-mprotect-g3-f8f5278d4140 Best regards, -- Dave Vasilevsky <dave(a)vasilevsky.ca>

5 days, 15 hours

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[PATCH 0/3] rust_binder: fix unsoundness due to combining List::remove with mem:take

by Alice Ryhl

See the first patch for details on the bug. Signed-off-by: Alice Ryhl <aliceryhl(a)google.com> --- Alice Ryhl (3): rust_binder: fix race condition on death_list rust_binder: avoid mem::take on delivered_deaths rust: list: add warning to List::remove docs about mem::take drivers/android/binder/node.rs | 6 +++--- drivers/android/binder/process.rs | 8 ++++++-- rust/kernel/list.rs | 3 +++ 3 files changed, 12 insertions(+), 5 deletions(-) --- base-commit: 211ddde0823f1442e4ad052a2f30f050145ccada change-id: 20251111-binder-fix-list-remove-41c29c75ffc9 Best regards, -- Alice Ryhl <aliceryhl(a)google.com>

5 days, 15 hours

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[PATCH] mm, swap: fix potential UAF issue for VMA readahead

by Kairui Song

From: Kairui Song <kasong(a)tencent.com> Since commit 78524b05f1a3 ("mm, swap: avoid redundant swap device pinning"), the common helper for allocating and preparing a folio in the swap cache layer no longer tries to get a swap device reference internally, because all callers of __read_swap_cache_async are already holding a swap entry reference. The repeated swap device pinning isn't needed on the same swap device. Caller of VMA readahead is also holding a reference to the target entry's swap device, but VMA readahead walks the page table, so it might encounter swap entries from other devices, and call __read_swap_cache_async on another device without holding a reference to it. So it is possible to cause a UAF when swapoff of device A raced with swapin on device B, and VMA readahead tries to read swap entries from device A. It's not easy to trigger, but in theory, it could cause real issues. Make VMA readahead try to get the device reference first if the swap device is a different one from the target entry. Cc: stable(a)vger.kernel.org Fixes: 78524b05f1a3 ("mm, swap: avoid redundant swap device pinning") Suggested-by: Huang Ying <ying.huang(a)linux.alibaba.com> Signed-off-by: Kairui Song <kasong(a)tencent.com> --- Sending as a new patch instead of V2 because the approach is very different. Previous patch: https://lore.kernel.org/linux-mm/20251110-revert-78524b05f1a3-v1-1-88313f2b… --- mm/swap_state.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/mm/swap_state.c b/mm/swap_state.c index 0cf9853a9232..da0481e163a4 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -745,6 +745,7 @@ static struct folio *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask, blk_start_plug(&plug); for (addr = start; addr < end; ilx++, addr += PAGE_SIZE) { + struct swap_info_struct *si = NULL; softleaf_t entry; if (!pte++) { @@ -759,8 +760,19 @@ static struct folio *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask, continue; pte_unmap(pte); pte = NULL; + /* + * Readahead entry may come from a device that we are not + * holding a reference to, try to grab a reference, or skip. + */ + if (swp_type(entry) != swp_type(targ_entry)) { + si = get_swap_device(entry); + if (!si) + continue; + } folio = __read_swap_cache_async(entry, gfp_mask, mpol, ilx, &page_allocated, false); + if (si) + put_swap_device(si); if (!folio) continue; if (page_allocated) { --- base-commit: 565d240810a6c9689817a9f3d08f80adf488ca59 change-id: 20251111-swap-fix-vma-uaf-bec70969250f Best regards, -- Kairui Song <kasong(a)tencent.com>

5 days, 16 hours

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[PATCH net v1 1/1] net: dsa: microchip: lan937x: Fix RGMII delay tuning

by Oleksij Rempel

Correct RGMII delay application logic in lan937x_set_tune_adj(). The function was missing `data16 &= ~PORT_TUNE_ADJ` before setting the new delay value. This caused the new value to be bitwise-OR'd with the existing PORT_TUNE_ADJ field instead of replacing it. For example, when setting the RGMII 2 TX delay on port 4, the intended TUNE_ADJUST value of 0 (RGMII_2_TX_DELAY_2NS) was incorrectly OR'd with the default 0x1B (from register value 0xDA3), leaving the delay at the wrong setting. This patch adds the missing mask to clear the field, ensuring the correct delay value is written. Physical measurements on the RGMII TX lines confirm the fix, showing the delay changing from ~1ns (before change) to ~2ns. While testing on i.MX 8MP showed this was within the platform's timing tolerance, it did not match the intended hardware-characterized value. Fixes: b19ac41faa3f ("net: dsa: microchip: apply rgmii tx and rx delay in phylink mac config") Signed-off-by: Oleksij Rempel <o.rempel(a)pengutronix.de> --- drivers/net/dsa/microchip/lan937x_main.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c index b1ae3b9de3d1..5a1496fff445 100644 --- a/drivers/net/dsa/microchip/lan937x_main.c +++ b/drivers/net/dsa/microchip/lan937x_main.c @@ -540,6 +540,7 @@ static void lan937x_set_tune_adj(struct ksz_device *dev, int port, ksz_pread16(dev, port, reg, &data16); /* Update tune Adjust */ + data16 &= ~PORT_TUNE_ADJ; data16 |= FIELD_PREP(PORT_TUNE_ADJ, val); ksz_pwrite16(dev, port, reg, data16); -- 2.47.3

5 days, 16 hours

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5 days, 17 hours

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[PATCH v2] intel_th: Fix error handling in intel_th_output_open

by Ma Ke

intel_th_output_open() calls bus_find_device_by_devt() which internally increments the device reference count via get_device(), but this reference is not properly released in several error paths. When device driver is unavailable, file operations cannot be obtained, or the driver's open method fails, the function returns without calling put_device(), leading to a permanent device reference count leak. This prevents the device from being properly released and could cause resource exhaustion over time. Found by code review. Cc: stable(a)vger.kernel.org Fixes: 39f4034693b7 ("intel_th: Add driver infrastructure for Intel(R) Trace Hub devices") Signed-off-by: Ma Ke <make24(a)iscas.ac.cn> --- Changes in v2: - modified the patch to fix uninitialized variable 'err' warnings. --- drivers/hwtracing/intel_th/core.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c index 47d9e6c3bac0..fdb9d022d875 100644 --- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -810,13 +810,17 @@ static int intel_th_output_open(struct inode *inode, struct file *file) int err; dev = bus_find_device_by_devt(&intel_th_bus, inode->i_rdev); - if (!dev || !dev->driver) - return -ENODEV; + if (!dev || !dev->driver) { + err = -ENODEV; + goto out_no_device; + } thdrv = to_intel_th_driver(dev->driver); fops = fops_get(thdrv->fops); - if (!fops) - return -ENODEV; + if (!fops) { + err = -ENODEV; + goto out_put_device; + } replace_fops(file, fops); @@ -824,10 +828,16 @@ static int intel_th_output_open(struct inode *inode, struct file *file) if (file->f_op->open) { err = file->f_op->open(inode, file); - return err; + if (err) + goto out_put_device; } return 0; + +out_put_device: + put_device(dev); +out_no_device: + return err; } static const struct file_operations intel_th_output_fops = { -- 2.17.1

5 days, 17 hours

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