June 2025 - Linux-stable-mirror

Re: [PATCH net] netrom: fix possible deadlock in nr_rt_device_down

by Jakub Kicinski

On Mon, 9 Jun 2025 16:16:32 -0700 David Ranch wrote: > I'm not sure what you mean by "the only user of this code". There are > many people using the Linux AX.25 + NETROM stack but we unfortunately > don't have a active kernel maintainer for this code today. Alright, sorry. Either way - these locks are not performance critical for you, right?

2 weeks, 2 days

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WTS Available laptops and Memory

by Exceptional One PC

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2 weeks, 2 days

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[PATCH v4 01/10] platform/x86/intel/pmt: fix a crashlog NULL pointer access

by Michael J. Ruhl

Usage of the intel_pmt_read() for binary sysfs, requires a pcidev. The current use of the endpoint value is only valid for telemetry endpoint usage. Without the ep, the crashlog usage causes the following NULL pointer exception: BUG: kernel NULL pointer dereference, address: 0000000000000000 Oops: Oops: 0000 [#1] SMP NOPTI RIP: 0010:intel_pmt_read+0x3b/0x70 [pmt_class] Code: Call Trace: <TASK> ? sysfs_kf_bin_read+0xc0/0xe0 kernfs_fop_read_iter+0xac/0x1a0 vfs_read+0x26d/0x350 ksys_read+0x6b/0xe0 __x64_sys_read+0x1d/0x30 x64_sys_call+0x1bc8/0x1d70 do_syscall_64+0x6d/0x110 Augment the inte_pmt_entry to include the pcidev to allow for access to the pcidev and avoid the NULL pointer exception. Fixes: 416eeb2e1fc7 ("platform/x86/intel/pmt: telemetry: Export API to read telemetry") Cc: <stable(a)vger.kernel.org> Signed-off-by: Michael J. Ruhl <michael.j.ruhl(a)intel.com> --- drivers/platform/x86/intel/pmt/class.c | 3 ++- drivers/platform/x86/intel/pmt/class.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/platform/x86/intel/pmt/class.c b/drivers/platform/x86/intel/pmt/class.c index 7233b654bbad..d046e8752173 100644 --- a/drivers/platform/x86/intel/pmt/class.c +++ b/drivers/platform/x86/intel/pmt/class.c @@ -97,7 +97,7 @@ intel_pmt_read(struct file *filp, struct kobject *kobj, if (count > entry->size - off) count = entry->size - off; - count = pmt_telem_read_mmio(entry->ep->pcidev, entry->cb, entry->header.guid, buf, + count = pmt_telem_read_mmio(entry->pcidev, entry->cb, entry->header.guid, buf, entry->base, off, count); return count; @@ -252,6 +252,7 @@ static int intel_pmt_populate_entry(struct intel_pmt_entry *entry, return -EINVAL; } + entry->pcidev = pci_dev; entry->guid = header->guid; entry->size = header->size; entry->cb = ivdev->priv_data; diff --git a/drivers/platform/x86/intel/pmt/class.h b/drivers/platform/x86/intel/pmt/class.h index b2006d57779d..f6ce80c4e051 100644 --- a/drivers/platform/x86/intel/pmt/class.h +++ b/drivers/platform/x86/intel/pmt/class.h @@ -39,6 +39,7 @@ struct intel_pmt_header { struct intel_pmt_entry { struct telem_endpoint *ep; + struct pci_dev *pcidev; struct intel_pmt_header header; struct bin_attribute pmt_bin_attr; struct kobject *kobj; -- 2.49.0

2 weeks, 2 days

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[PATCH] ASoC: sdw_utils: Fix potential NULL pointer deref in is_sdca_endpoint_present()

by Thorsten Blum

Check the return value of kzalloc() and exit early to avoid a potential NULL pointer dereference. Cc: stable(a)vger.kernel.org Fixes: 4f8ef33dd44a ("ASoC: soc_sdw_utils: skip the endpoint that doesn't present") Signed-off-by: Thorsten Blum <thorsten.blum(a)linux.dev> --- sound/soc/sdw_utils/soc_sdw_utils.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sound/soc/sdw_utils/soc_sdw_utils.c b/sound/soc/sdw_utils/soc_sdw_utils.c index 30f84f4e7637..b70cb3793d8f 100644 --- a/sound/soc/sdw_utils/soc_sdw_utils.c +++ b/sound/soc/sdw_utils/soc_sdw_utils.c @@ -1180,6 +1180,8 @@ static int is_sdca_endpoint_present(struct device *dev, int i; dlc = kzalloc(sizeof(*dlc), GFP_KERNEL); + if (!dlc) + return -ENOMEM; adr_end = &adr_dev->endpoints[end_index]; dai_info = &codec_info->dais[adr_end->num]; -- 2.49.0

2 weeks, 2 days

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FAILED: patch "[PATCH] dt-bindings: pwm: adi,axi-pwmgen: Fix clocks" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x e683131e64f71e957ca77743cb3d313646157329 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025060734-elated-juvenile-da5c@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e683131e64f71e957ca77743cb3d313646157329 Mon Sep 17 00:00:00 2001 From: David Lechner <dlechner(a)baylibre.com> Date: Thu, 29 May 2025 11:53:19 -0500 Subject: [PATCH] dt-bindings: pwm: adi,axi-pwmgen: Fix clocks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix a shortcoming in the bindings that doesn't allow for a separate external clock. The AXI PWMGEN IP block has a compile option ASYNC_CLK_EN that allows the use of an external clock for the PWM output separate from the AXI clock that runs the peripheral. This was missed in the original bindings and so users were writing dts files where the one and only clock specified would be the external clock, if there was one, incorrectly missing the separate AXI clock. The correct bindings are that the AXI clock is always required and the external clock is optional (must be given only when HDL compile option ASYNC_CLK_EN=1). Fixes: 1edf2c2a2841 ("dt-bindings: pwm: Add AXI PWM generator") Cc: stable(a)vger.kernel.org Signed-off-by: David Lechner <dlechner(a)baylibre.com> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski(a)linaro.org> Link: https://lore.kernel.org/r/20250529-pwm-axi-pwmgen-add-external-clock-v3-2-5… Signed-off-by: Uwe Kleine-König <ukleinek(a)kernel.org> diff --git a/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml b/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml index 45e112d0efb4..5575c58357d6 100644 --- a/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml +++ b/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml @@ -30,11 +30,19 @@ properties: const: 3 clocks: - maxItems: 1 + minItems: 1 + maxItems: 2 + + clock-names: + minItems: 1 + items: + - const: axi + - const: ext required: - reg - clocks + - clock-names unevaluatedProperties: false @@ -43,6 +51,7 @@ examples: pwm@44b00000 { compatible = "adi,axi-pwmgen-2.00.a"; reg = <0x44b00000 0x1000>; - clocks = <&spi_clk>; + clocks = <&fpga_clk>, <&spi_clk>; + clock-names = "axi", "ext"; #pwm-cells = <3>; };

2 weeks, 2 days

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[PATCH] sched: Fix preemption string of preempt_dynamic_none

by Thomas Weißschuh

Zero is a valid value for "preempt_dynamic_mode", namely "preempt_dynamic_none". Fix the off-by-one in preempt_model_str(), so that "preempty_dynamic_none" is correctly formatted as PREEMPT(none) instead of PREEMPT(undef). Fixes: 8bdc5daaa01e ("sched: Add a generic function to return the preemption string") Cc: stable(a)vger.kernel.org Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dce50fa57471dffc4311b9d393ae300a43d38d20..021b0a703d094b3386c5ba50e0e111e3a7c2b3df 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7663,7 +7663,7 @@ const char *preempt_model_str(void) if (IS_ENABLED(CONFIG_PREEMPT_DYNAMIC)) { seq_buf_printf(&s, "(%s)%s", - preempt_dynamic_mode > 0 ? + preempt_dynamic_mode >= 0 ? preempt_modes[preempt_dynamic_mode] : "undef", brace ? "}" : ""); return seq_buf_str(&s); --- base-commit: 546b1c9e93c2bb8cf5ed24e0be1c86bb089b3253 change-id: 20250603-preempt-str-none-d21231cc2238 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

2 weeks, 2 days

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[PATCH 5.10] usb: dwc3: dwc3-qcom: Add missing platform_device_put() in dwc3_qcom_acpi_register_core

by Denis Arefev

From: Miaoqian Lin <linmq006(a)gmail.com> commit fa0ef93868a6062babe1144df2807a8b1d4924d2 upstream. Add the missing platform_device_put() before return from dwc3_qcom_acpi_register_core in the error handling case. Fixes: 2bc02355f8ba ("usb: dwc3: qcom: Add support for booting with ACPI") Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com> Link: https://lore.kernel.org/r/20211231113641.31474-1-linmq006@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> [Denis: minor fix to resolve merge conflict and add tag Fixes.] Signed-off-by: Denis Arefev <arefev(a)swemel.ru> --- Backport fix for CVE-2023-22995 Link: https://nvd.nist.gov/vuln/detail/cve-2023-22995 --- drivers/usb/dwc3/dwc3-qcom.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c index db3559a10207..568973582b75 100644 --- a/drivers/usb/dwc3/dwc3-qcom.c +++ b/drivers/usb/dwc3/dwc3-qcom.c @@ -622,8 +622,10 @@ static int dwc3_qcom_acpi_register_core(struct platform_device *pdev) qcom->dwc3->dev.coherent_dma_mask = dev->coherent_dma_mask; child_res = kcalloc(2, sizeof(*child_res), GFP_KERNEL); - if (!child_res) + if (!child_res) { + platform_device_put(qcom->dwc3); return -ENOMEM; + } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { @@ -659,10 +661,15 @@ static int dwc3_qcom_acpi_register_core(struct platform_device *pdev) } ret = platform_device_add(qcom->dwc3); - if (ret) + if (ret) { dev_err(&pdev->dev, "failed to add device\n"); + goto out; + } + kfree(child_res); + return 0; out: + platform_device_put(qcom->dwc3); kfree(child_res); return ret; } -- 2.43.0

2 weeks, 2 days

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Re: Patch "USB: serial: bus: fix const issue in usb_serial_device_match()" has been added to the 6.15-stable tree

by Johan Hovold

Hi Sasha, On Tue, Jun 10, 2025 at 08:18:13AM -0400, Sasha Levin wrote: > This is a note to let you know that I've just added the patch titled > > USB: serial: bus: fix const issue in usb_serial_device_match() > > to the 6.15-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… > > The filename of the patch is: > usb-serial-bus-fix-const-issue-in-usb_serial_device_.patch > and it can be found in the queue-6.15 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable(a)vger.kernel.org> know about it. > > > > commit 0e91be50efc1a26ec9047dadc980631d31ef8578 > Author: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> > Date: Wed May 21 15:41:34 2025 +0200 > > USB: serial: bus: fix const issue in usb_serial_device_match() > > [ Upstream commit 92cd405b648605db4da866f3b9818b271ae84ef0 ] > > usb_serial_device_match() takes a const pointer, and then decides to > cast it away into a non-const one, which is not a good thing to do > overall. Fix this up by properly setting the pointers to be const to > preserve that attribute. > > Fixes: d69d80484598 ("driver core: have match() callback in struct bus_type take a const *") > Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> > Signed-off-by: Johan Hovold <johan(a)kernel.org> > Signed-off-by: Sasha Levin <sashal(a)kernel.org> This patch does not need to be backported and I left out the stable patch on purpose as usual. Please drop. Johan

2 weeks, 2 days

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[PATCH] ipmi: fix underflow in ipmi_create_user()

by Yi Yang

Syzkaller reported this bug: ================================================================== BUG: KASAN: global-out-of-bounds in instrument_atomic_read_write include/linux/instrumented.h:96 [inline] BUG: KASAN: global-out-of-bounds in atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline] BUG: KASAN: global-out-of-bounds in ipmi_create_user.part.0+0x5e5/0x790 drivers/char/ipmi/ipmi_msghandler.c:1291 Write of size 4 at addr ffffffff8fc6a438 by task syz.5.1074/5888 CPU: 0 PID: 5888 Comm: syz.5.1074 Not tainted 6.6.0+ #60 ...... Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x72/0xa0 lib/dump_stack.c:106 print_address_description.constprop.0+0x6b/0x3d0 mm/kasan/report.c:364 print_report+0xba/0x280 mm/kasan/report.c:475 kasan_report+0xa9/0xe0 mm/kasan/report.c:588 check_region_inline mm/kasan/generic.c:181 [inline] kasan_check_range+0x100/0x1c0 mm/kasan/generic.c:187 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline] ipmi_create_user.part.0+0x5e5/0x790 drivers/char/ipmi/ipmi_msghandler.c:1291 ipmi_create_user+0x56/0x80 drivers/char/ipmi/ipmi_msghandler.c:1236 ipmi_open+0xac/0x2b0 drivers/char/ipmi/ipmi_devintf.c:97 chrdev_open+0x276/0x700 fs/char_dev.c:414 do_dentry_open+0x6a7/0x1410 fs/open.c:929 vfs_open+0xd1/0x440 fs/open.c:1060 do_open+0x957/0x10d0 fs/namei.c:3671 path_openat+0x258/0x770 fs/namei.c:3830 do_filp_open+0x1c7/0x410 fs/namei.c:3857 do_sys_openat2+0x5bd/0x6a0 fs/open.c:1428 do_sys_open fs/open.c:1443 [inline] __do_sys_openat fs/open.c:1459 [inline] __se_sys_openat fs/open.c:1454 [inline] __x64_sys_openat+0x17a/0x210 fs/open.c:1454 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x78/0xe2 RIP: 0033:0x54d2cd Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4751920048 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000796080 RCX: 000000000054d2cd RDX: 0000000000000000 RSI: 0000000020004280 RDI: ffffffffffffff9c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000001e R11: 0000000000000246 R12: 000000000079608c R13: 0000000000000000 R14: 0000000000796080 R15: 00007f4751900000 </TASK> The buggy address belongs to the variable: ipmi_interfaces+0x38/0x40 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x45a6a flags: 0x3fffff00004000(reserved|node=0|zone=1|lastcpupid=0x1fffff) raw: 003fffff00004000 ffffea0001169a88 ffffea0001169a88 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffffffff8fc6a300: 00 00 00 00 f9 f9 f9 f9 00 00 00 00 f9 f9 f9 f9 ffffffff8fc6a380: 00 00 f9 f9 f9 f9 f9 f9 00 00 00 00 f9 f9 f9 f9 >ffffffff8fc6a400: 00 00 f9 f9 f9 f9 f9 f9 00 00 00 00 f9 f9 f9 f9 ^ ffffffff8fc6a480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffffff8fc6a500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9 ================================================================== In the ipmi_create_user() function, the intf->nr_users variable has an underflow issue. Specifically, on the exception path (goto out_kfree;) before atomic_add_return(), calling atomic_dec() when intf->nr_users has not been incremented will result in an underflow. The relevant code has been completely rewritten in the next tree and has been fixed with commit 9e91f8a6c868 ("ipmi:msghandler: Remove srcu for the ipmi_interfaces list"). However, the issue still exists in the 5.19+ stable branches and needs to be fixed on those branches. Cc: stable(a)vger.kernel.org # 5.19+ Fixes: 8e76741c3d8b ("ipmi: Add a limit on the number of users that may use IPMI") Signed-off-by: Yi Yang <yiyang13(a)huawei.com> --- drivers/char/ipmi/ipmi_msghandler.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index 186f1fee7534..0293fad2f4f2 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -1246,18 +1246,18 @@ int ipmi_create_user(unsigned int if_num, found: if (atomic_add_return(1, &intf->nr_users) > max_users) { rv = -EBUSY; - goto out_kfree; + goto out_dec; } INIT_WORK(&new_user->remove_work, free_user_work); rv = init_srcu_struct(&new_user->release_barrier); if (rv) - goto out_kfree; + goto out_dec; if (!try_module_get(intf->owner)) { rv = -ENODEV; - goto out_kfree; + goto out_dec; } /* Note that each existing user holds a refcount to the interface. */ @@ -1281,8 +1281,9 @@ int ipmi_create_user(unsigned int if_num, *user = new_user; return 0; -out_kfree: +out_dec: atomic_dec(&intf->nr_users); +out_kfree: srcu_read_unlock(&ipmi_interfaces_srcu, index); vfree(new_user); return rv; -- 2.25.1

2 weeks, 2 days

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Re: [PATCH v2] mm/shmem, swap: fix softlockup with mTHP swapin

by Kairui Song

On Tue, Jun 10, 2025 at 1:18 AM Kairui Song <ryncsn(a)gmail.com> wrote: > > From: Kairui Song <kasong(a)tencent.com> > > Following softlockup can be easily reproduced on my test machine with: > > echo always > /sys/kernel/mm/transparent_hugepage/hugepages-64kB/enabled > swapon /dev/zram0 # zram0 is a 48G swap device > mkdir -p /sys/fs/cgroup/memory/test > echo 1G > /sys/fs/cgroup/test/memory.max > echo $BASHPID > /sys/fs/cgroup/test/cgroup.procs > while true; do > dd if=/dev/zero of=/tmp/test.img bs=1M count=5120 > cat /tmp/test.img > /dev/null > rm /tmp/test.img > done > > Then after a while: > watchdog: BUG: soft lockup - CPU#0 stuck for 763s! [cat:5787] > Modules linked in: zram virtiofs > CPU: 0 UID: 0 PID: 5787 Comm: cat Kdump: loaded Tainted: G L 6.15.0.orig-gf3021d9246bc-dirty #118 PREEMPT(voluntary)· > Tainted: [L]=SOFTLOCKUP > Hardware name: Red Hat KVM/RHEL-AV, BIOS 0.0.0 02/06/2015 > RIP: 0010:mpol_shared_policy_lookup+0xd/0x70 > Code: e9 b8 b4 ff ff 31 c0 c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 0f 1f 44 00 00 41 54 55 53 <48> 8b 1f 48 85 db 74 41 4c 8d 67 08 48 89 fb 48 89 f5 4c 89 e7 e8 > RSP: 0018:ffffc90002b1fc28 EFLAGS: 00000202 > RAX: 00000000001c20ca RBX: 0000000000724e1e RCX: 0000000000000001 > RDX: ffff888118e214c8 RSI: 0000000000057d42 RDI: ffff888118e21518 > RBP: 000000000002bec8 R08: 0000000000000001 R09: 0000000000000000 > R10: 0000000000000bf4 R11: 0000000000000000 R12: 0000000000000001 > R13: 00000000001c20ca R14: 00000000001c20ca R15: 0000000000000000 > FS: 00007f03f995c740(0000) GS:ffff88a07ad9a000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f03f98f1000 CR3: 0000000144626004 CR4: 0000000000770eb0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > PKRU: 55555554 > Call Trace: > <TASK> > shmem_alloc_folio+0x31/0xc0 > shmem_swapin_folio+0x309/0xcf0 > ? filemap_get_entry+0x117/0x1e0 > ? xas_load+0xd/0xb0 > ? filemap_get_entry+0x101/0x1e0 > shmem_get_folio_gfp+0x2ed/0x5b0 > shmem_file_read_iter+0x7f/0x2e0 > vfs_read+0x252/0x330 > ksys_read+0x68/0xf0 > do_syscall_64+0x4c/0x1c0 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > RIP: 0033:0x7f03f9a46991 > Code: 00 48 8b 15 81 14 10 00 f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 20 ad 01 00 f3 0f 1e fa 80 3d 35 97 10 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec > RSP: 002b:00007fff3c52bd28 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 > RAX: ffffffffffffffda RBX: 0000000000040000 RCX: 00007f03f9a46991 > RDX: 0000000000040000 RSI: 00007f03f98ba000 RDI: 0000000000000003 > RBP: 00007fff3c52bd50 R08: 0000000000000000 R09: 00007f03f9b9a380 > R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000040000 > R13: 00007f03f98ba000 R14: 0000000000000003 R15: 0000000000000000 > </TASK> > > The reason is simple, readahead brought some order 0 folio in swap > cache, and the swapin mTHP folio being allocated is in confict with it, > so swapcache_prepare fails and causes shmem_swap_alloc_folio to return > -EEXIST, and shmem simply retries again and again causing this loop. > > Fix it by applying a similar fix for anon mTHP swapin. > > The performance change is very slight, time of swapin 10g zero folios > with shmem (test for 12 times): > Before: 2.47s > After: 2.48s > > Fixes: 1dd44c0af4fa1 ("mm: shmem: skip swapcache for swapin of synchronous swap device") > Signed-off-by: Kairui Song <kasong(a)tencent.com> > > --- > > V1: https://lore.kernel.org/linux-mm/20250608192713.95875-1-ryncsn@gmail.com/ > Updates: > - Move non_swapcache_batch check before swapcache_prepare, I was > expecting this could improve the performance, turns out it barely > helps and may even cause more overhead in some cases. [ Barry Song ] > - Remove zero map check, no need to do that for shmem [ Barry Song, > Baolin Wang ] > - Fix build bot error. > > mm/memory.c | 20 -------------------- > mm/shmem.c | 4 +++- > mm/swap.h | 23 +++++++++++++++++++++++ > 3 files changed, 26 insertions(+), 21 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index 9ead7ab07e8e..3845ed068d74 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4313,26 +4313,6 @@ static struct folio *__alloc_swap_folio(struct vm_fault *vmf) > } > > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > -static inline int non_swapcache_batch(swp_entry_t entry, int max_nr) > -{ > - struct swap_info_struct *si = swp_swap_info(entry); > - pgoff_t offset = swp_offset(entry); > - int i; > - > - /* > - * While allocating a large folio and doing swap_read_folio, which is > - * the case the being faulted pte doesn't have swapcache. We need to > - * ensure all PTEs have no cache as well, otherwise, we might go to > - * swap devices while the content is in swapcache. > - */ > - for (i = 0; i < max_nr; i++) { > - if ((si->swap_map[offset + i] & SWAP_HAS_CACHE)) > - return i; > - } > - > - return i; > -} > - > /* > * Check if the PTEs within a range are contiguous swap entries > * and have consistent swapcache, zeromap. > diff --git a/mm/shmem.c b/mm/shmem.c > index 73182e904f9c..a4fdfbd086f1 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -2256,6 +2256,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, > folio = swap_cache_get_folio(swap, NULL, 0); > order = xa_get_order(&mapping->i_pages, index); > if (!folio) { > + int nr_pages = 1 << order; > bool fallback_order0 = false; > > /* Or update major stats only when swapin succeeds?? */ > @@ -2271,7 +2272,8 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, > * to swapin order-0 folio, as well as for zswap case. > */ > if (order > 0 && ((vma && unlikely(userfaultfd_armed(vma))) || > - !zswap_never_enabled())) > + !zswap_never_enabled() || > + non_swapcache_batch(swap, nr_pages) != nr_pages)) > fallback_order0 = true; > > /* Skip swapcache for synchronous device. */ > diff --git a/mm/swap.h b/mm/swap.h > index e87a0f19a0ee..911ad5ff0f89 100644 > --- a/mm/swap.h > +++ b/mm/swap.h > @@ -108,6 +108,25 @@ static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, > return find_next_bit(sis->zeromap, end, start) - start; > } > > +static inline int non_swapcache_batch(swp_entry_t entry, int max_nr) > +{ > + struct swap_info_struct *si = swp_swap_info(entry); > + pgoff_t offset = swp_offset(entry); > + int i; > + > + /* > + * While allocating a large folio and doing mTHP swapin, we need to > + * ensure all entries are not cached, otherwise, the mTHP folio will > + * be in conflict with the folio in swap cache. > + */ > + for (i = 0; i < max_nr; i++) { > + if ((si->swap_map[offset + i] & SWAP_HAS_CACHE)) > + return i; > + } > + > + return i; > +} > + > #else /* CONFIG_SWAP */ > struct swap_iocb; > static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug) > @@ -202,6 +221,10 @@ static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, > return 0; > } > > +static inline int non_swapcache_batch(swp_entry_t entry, int max_nr) > +{ > + return 0; > +} > #endif /* CONFIG_SWAP */ > > /** > -- > 2.49.0 > I really should Cc stable for this, sorry I forgot it. Cc: stable(a)vger.kernel.org # 6.14

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Linux-stable-mirror June 2025