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FAILED: patch "[PATCH] s390: Disable ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 64e2f60f355e556337fcffe80b9bcff1b22c9c42 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025110340-immature-headband-9af4@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 64e2f60f355e556337fcffe80b9bcff1b22c9c42 Mon Sep 17 00:00:00 2001 From: Heiko Carstens <hca(a)linux.ibm.com> Date: Thu, 30 Oct 2025 15:55:05 +0100 Subject: [PATCH] s390: Disable ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP As reported by Luiz Capitulino enabling HVO on s390 leads to reproducible crashes. The problem is that kernel page tables are modified without flushing corresponding TLB entries. Even if it looks like the empty flush_tlb_all() implementation on s390 is the problem, it is actually a different problem: on s390 it is not allowed to replace an active/valid page table entry with another valid page table entry without the detour over an invalid entry. A direct replacement may lead to random crashes and/or data corruption. In order to invalidate an entry special instructions have to be used (e.g. ipte or idte). Alternatively there are also special instructions available which allow to replace a valid entry with a different valid entry (e.g. crdte or cspg). Given that the HVO code currently does not provide the hooks to allow for an implementation which is compliant with the s390 architecture requirements, disable ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP again, which is basically a revert of the original patch which enabled it. Reported-by: Luiz Capitulino <luizcap(a)redhat.com> Closes: https://lore.kernel.org/all/20251028153930.37107-1-luizcap@redhat.com/ Fixes: 00a34d5a99c0 ("s390: select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP") Cc: stable(a)vger.kernel.org Tested-by: Luiz Capitulino <luizcap(a)redhat.com> Reviewed-by: Gerald Schaefer <gerald.schaefer(a)linux.ibm.com> Reviewed-by: David Hildenbrand <david(a)redhat.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index c4145672ca34..df22b10d9141 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -158,7 +158,6 @@ config S390 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM select ARCH_WANT_KERNEL_PMD_MKWRITE select ARCH_WANT_LD_ORPHAN_WARN - select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP select ARCH_WANTS_THP_SWAP select BUILDTIME_TABLE_SORT select CLONE_BACKWARDS2

2 weeks, 1 day

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FAILED: patch "[PATCH] drm/sched: Fix race in drm_sched_entity_select_rq()" 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 d25e3a610bae03bffc5c14b5d944a5d0cd844678 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025110342-exhume-mankind-5952@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From d25e3a610bae03bffc5c14b5d944a5d0cd844678 Mon Sep 17 00:00:00 2001 From: Philipp Stanner <phasta(a)kernel.org> Date: Wed, 22 Oct 2025 08:34:03 +0200 Subject: [PATCH] drm/sched: Fix race in drm_sched_entity_select_rq() In a past bug fix it was forgotten that entity access must be protected by the entity lock. That's a data race and potentially UB. Move the spin_unlock() to the appropriate position. Cc: stable(a)vger.kernel.org # v5.13+ Fixes: ac4eb83ab255 ("drm/sched: select new rq even if there is only one v3") Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin(a)igalia.com> Signed-off-by: Philipp Stanner <phasta(a)kernel.org> Link: https://patch.msgid.link/20251022063402.87318-2-phasta@kernel.org diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index 5a4697f636f2..aa222166de58 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -552,10 +552,11 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity) drm_sched_rq_remove_entity(entity->rq, entity); entity->rq = rq; } - spin_unlock(&entity->lock); if (entity->num_sched_list == 1) entity->sched_list = NULL; + + spin_unlock(&entity->lock); } /**

2 weeks, 1 day

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[PATCH net v3 1/3] net,mptcp: fix proto fallback detection with BPF sockmap

by Jiayuan Chen

When the server has MPTCP enabled but receives a non-MP-capable request from a client, it calls mptcp_fallback_tcp_ops(). Since non-MPTCP connections are allowed to use sockmap, which replaces sk->sk_prot, using sk->sk_prot to determine the IP version in mptcp_fallback_tcp_ops() becomes unreliable. This can lead to assigning incorrect ops to sk->sk_socket->ops. Additionally, when BPF Sockmap modifies the protocol handlers, the original WARN_ON_ONCE(sk->sk_prot != &tcp_prot) check would falsely trigger warnings. Fix this by using the more stable sk_family to distinguish between IPv4 and IPv6 connections, ensuring correct fallback protocol operations are selected even when BPF Sockmap has modified the socket protocol handlers. Fixes: 0b4f33def7bb ("mptcp: fix tcp fallback crash") Cc: <stable(a)vger.kernel.org> Signed-off-by: Jiayuan Chen <jiayuan.chen(a)linux.dev> Reviewed-by: Jakub Sitnicki <jakub(a)cloudflare.com> --- net/mptcp/protocol.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 0292162a14ee..2393741bc310 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -61,11 +61,16 @@ static u64 mptcp_wnd_end(const struct mptcp_sock *msk) static const struct proto_ops *mptcp_fallback_tcp_ops(const struct sock *sk) { + /* When BPF sockmap is used, it may replace sk->sk_prot. + * Using sk_family is a reliable way to determine the IP version. + */ + unsigned short family = READ_ONCE(sk->sk_family); + #if IS_ENABLED(CONFIG_MPTCP_IPV6) - if (sk->sk_prot == &tcpv6_prot) + if (family == AF_INET6) return &inet6_stream_ops; #endif - WARN_ON_ONCE(sk->sk_prot != &tcp_prot); + WARN_ON_ONCE(family != AF_INET); return &inet_stream_ops; } -- 2.43.0

2 weeks, 1 day

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[tip: x86/urgent] x86/amd_node: Fix AMD root device caching

by tip-bot2 for Yazen Ghannam

The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 0a4b61d9c2e496b5f0a10e29e355a1465c8738bb Gitweb: https://git.kernel.org/tip/0a4b61d9c2e496b5f0a10e29e355a1465c8738bb Author: Yazen Ghannam <yazen.ghannam(a)amd.com> AuthorDate: Tue, 28 Oct 2025 21:35:42 Committer: Borislav Petkov (AMD) <bp(a)alien8.de> CommitterDate: Mon, 03 Nov 2025 12:46:57 +01:00 x86/amd_node: Fix AMD root device caching Recent AMD node rework removed the "search and count" method of caching AMD root devices. This depended on the value from a Data Fabric register that was expected to hold the PCI bus of one of the root devices attached to that fabric. However, this expectation is incorrect. The register, when read from PCI config space, returns the bitwise-OR of the buses of all attached root devices. This behavior is benign on AMD reference design boards, since the bus numbers are aligned. This results in a bitwise-OR value matching one of the buses. For example, 0x00 | 0x40 | 0xA0 | 0xE0 = 0xE0. This behavior breaks on boards where the bus numbers are not exactly aligned. For example, 0x00 | 0x07 | 0xE0 | 0x15 = 0x1F. The examples above are for AMD node 0. The first root device on other nodes will not be 0x00. The first root device for other nodes will depend on the total number of root devices, the system topology, and the specific PCI bus number assignment. For example, a system with 2 AMD nodes could have this: Node 0 : 0x00 0x07 0x0e 0x15 Node 1 : 0x1c 0x23 0x2a 0x31 The bus numbering style in the reference boards is not a requirement. The numbering found in other boards is not incorrect. Therefore, the root device caching method needs to be adjusted. Go back to the "search and count" method used before the recent rework. Search for root devices using PCI class code rather than fixed PCI IDs. This keeps the goal of the rework (remove dependency on PCI IDs) while being able to support various board designs. Merge helper functions to reduce code duplication. [ bp: Reflow comment. ] Fixes: 40a5f6ffdfc8 ("x86/amd_nb: Simplify root device search") Signed-off-by: Yazen Ghannam <yazen.ghannam(a)amd.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Cc: stable(a)vger.kernel.org Link: https://patch.msgid.link/all/20251028-fix-amd-root-v2-1-843e38f8be2c@amd.com --- arch/x86/include/asm/amd/node.h | 1 +- arch/x86/kernel/amd_node.c | 150 ++++++++++--------------------- 2 files changed, 51 insertions(+), 100 deletions(-) diff --git a/arch/x86/include/asm/amd/node.h b/arch/x86/include/asm/amd/node.h index 23fe617..a672b87 100644 --- a/arch/x86/include/asm/amd/node.h +++ b/arch/x86/include/asm/amd/node.h @@ -23,7 +23,6 @@ #define AMD_NODE0_PCI_SLOT 0x18 struct pci_dev *amd_node_get_func(u16 node, u8 func); -struct pci_dev *amd_node_get_root(u16 node); static inline u16 amd_num_nodes(void) { diff --git a/arch/x86/kernel/amd_node.c b/arch/x86/kernel/amd_node.c index a40176b..3d0a476 100644 --- a/arch/x86/kernel/amd_node.c +++ b/arch/x86/kernel/amd_node.c @@ -34,62 +34,6 @@ struct pci_dev *amd_node_get_func(u16 node, u8 func) return pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(AMD_NODE0_PCI_SLOT + node, func)); } -#define DF_BLK_INST_CNT 0x040 -#define DF_CFG_ADDR_CNTL_LEGACY 0x084 -#define DF_CFG_ADDR_CNTL_DF4 0xC04 - -#define DF_MAJOR_REVISION GENMASK(27, 24) - -static u16 get_cfg_addr_cntl_offset(struct pci_dev *df_f0) -{ - u32 reg; - - /* - * Revision fields added for DF4 and later. - * - * Major revision of '0' is found pre-DF4. Field is Read-as-Zero. - */ - if (pci_read_config_dword(df_f0, DF_BLK_INST_CNT, &reg)) - return 0; - - if (reg & DF_MAJOR_REVISION) - return DF_CFG_ADDR_CNTL_DF4; - - return DF_CFG_ADDR_CNTL_LEGACY; -} - -struct pci_dev *amd_node_get_root(u16 node) -{ - struct pci_dev *root; - u16 cntl_off; - u8 bus; - - if (!cpu_feature_enabled(X86_FEATURE_ZEN)) - return NULL; - - /* - * D18F0xXXX [Config Address Control] (DF::CfgAddressCntl) - * Bits [7:0] (SecBusNum) holds the bus number of the root device for - * this Data Fabric instance. The segment, device, and function will be 0. - */ - struct pci_dev *df_f0 __free(pci_dev_put) = amd_node_get_func(node, 0); - if (!df_f0) - return NULL; - - cntl_off = get_cfg_addr_cntl_offset(df_f0); - if (!cntl_off) - return NULL; - - if (pci_read_config_byte(df_f0, cntl_off, &bus)) - return NULL; - - /* Grab the pointer for the actual root device instance. */ - root = pci_get_domain_bus_and_slot(0, bus, 0); - - pci_dbg(root, "is root for AMD node %u\n", node); - return root; -} - static struct pci_dev **amd_roots; /* Protect the PCI config register pairs used for SMN. */ @@ -274,51 +218,21 @@ DEFINE_SHOW_STORE_ATTRIBUTE(smn_node); DEFINE_SHOW_STORE_ATTRIBUTE(smn_address); DEFINE_SHOW_STORE_ATTRIBUTE(smn_value); -static int amd_cache_roots(void) -{ - u16 node, num_nodes = amd_num_nodes(); - - amd_roots = kcalloc(num_nodes, sizeof(*amd_roots), GFP_KERNEL); - if (!amd_roots) - return -ENOMEM; - - for (node = 0; node < num_nodes; node++) - amd_roots[node] = amd_node_get_root(node); - - return 0; -} - -static int reserve_root_config_spaces(void) +static struct pci_dev *get_next_root(struct pci_dev *root) { - struct pci_dev *root = NULL; - struct pci_bus *bus = NULL; - - while ((bus = pci_find_next_bus(bus))) { - /* Root device is Device 0 Function 0 on each Primary Bus. */ - root = pci_get_slot(bus, 0); - if (!root) + while ((root = pci_get_class(PCI_CLASS_BRIDGE_HOST << 8, root))) { + /* Root device is Device 0 Function 0. */ + if (root->devfn) continue; if (root->vendor != PCI_VENDOR_ID_AMD && root->vendor != PCI_VENDOR_ID_HYGON) continue; - pci_dbg(root, "Reserving PCI config space\n"); - - /* - * There are a few SMN index/data pairs and other registers - * that shouldn't be accessed by user space. - * So reserve the entire PCI config space for simplicity rather - * than covering specific registers piecemeal. - */ - if (!pci_request_config_region_exclusive(root, 0, PCI_CFG_SPACE_SIZE, NULL)) { - pci_err(root, "Failed to reserve config space\n"); - return -EEXIST; - } + break; } - smn_exclusive = true; - return 0; + return root; } static bool enable_dfs; @@ -332,7 +246,8 @@ __setup("amd_smn_debugfs_enable", amd_smn_enable_dfs); static int __init amd_smn_init(void) { - int err; + u16 count, num_roots, roots_per_node, node, num_nodes; + struct pci_dev *root; if (!cpu_feature_enabled(X86_FEATURE_ZEN)) return 0; @@ -342,13 +257,48 @@ static int __init amd_smn_init(void) if (amd_roots) return 0; - err = amd_cache_roots(); - if (err) - return err; + num_roots = 0; + root = NULL; + while ((root = get_next_root(root))) { + pci_dbg(root, "Reserving PCI config space\n"); - err = reserve_root_config_spaces(); - if (err) - return err; + /* + * There are a few SMN index/data pairs and other registers + * that shouldn't be accessed by user space. So reserve the + * entire PCI config space for simplicity rather than covering + * specific registers piecemeal. + */ + if (!pci_request_config_region_exclusive(root, 0, PCI_CFG_SPACE_SIZE, NULL)) { + pci_err(root, "Failed to reserve config space\n"); + return -EEXIST; + } + + num_roots++; + } + + pr_debug("Found %d AMD root devices\n", num_roots); + + if (!num_roots) + return -ENODEV; + + num_nodes = amd_num_nodes(); + amd_roots = kcalloc(num_nodes, sizeof(*amd_roots), GFP_KERNEL); + if (!amd_roots) + return -ENOMEM; + + roots_per_node = num_roots / num_nodes; + + count = 0; + node = 0; + root = NULL; + while (node < num_nodes && (root = get_next_root(root))) { + /* Use one root for each node and skip the rest. */ + if (count++ % roots_per_node) + continue; + + pci_dbg(root, "is root for AMD node %u\n", node); + amd_roots[node++] = root; + } if (enable_dfs) { debugfs_dir = debugfs_create_dir("amd_smn", arch_debugfs_dir); @@ -358,6 +308,8 @@ static int __init amd_smn_init(void) debugfs_create_file("value", 0600, debugfs_dir, NULL, &smn_value_fops); } + smn_exclusive = true; + return 0; }

2 weeks, 1 day

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[PATCH] usb: xhci: Check kcalloc_node() when allocating interrupter array in xhci_mem_init()

by Guangshuo Li

kcalloc_node() may fail. When the interrupter array allocation returns NULL, subsequent code uses xhci->interrupters (e.g. in xhci_add_interrupter() and in cleanup paths), leading to a potential NULL pointer dereference. Check the allocation and bail out to the existing fail path to avoid the NULL dereference. Fixes: c99b38c412343 ("xhci: add support to allocate several interrupters") Cc: stable(a)vger.kernel.org Signed-off-by: Guangshuo Li <lgs201920130244(a)gmail.com> --- drivers/usb/host/xhci-mem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index d698095fc88d..da257856e864 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -2505,7 +2505,8 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags) "Allocating primary event ring"); xhci->interrupters = kcalloc_node(xhci->max_interrupters, sizeof(*xhci->interrupters), flags, dev_to_node(dev)); - + if (!xhci->interrupters) + goto fail; ir = xhci_alloc_interrupter(xhci, 0, flags); if (!ir) goto fail; -- 2.43.0

2 weeks, 1 day

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[PATCH] phy: Fix error handling in tegra_xusb_pad_init

by Ma Ke

If device_add() fails, do not use device_unregister() for error handling. device_unregister() consists two functions: device_del() and put_device(). device_unregister() should only be called after device_add() succeeded because device_del() undoes what device_add() does if successful. Change device_unregister() to put_device() call before returning from the function. As comment of device_add() says, 'if device_add() succeeds, you should call device_del() when you want to get rid of it. If device_add() has not succeeded, use only put_device() to drop the reference count'. Found by code review. Cc: stable(a)vger.kernel.org Fixes: 78876f71b3e9 ("media: pci: intel: ivsc: Add ACE submodule") Signed-off-by: Ma Ke <make24(a)iscas.ac.cn> --- drivers/phy/tegra/xusb.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c index c89df95aa6ca..d89493d68699 100644 --- a/drivers/phy/tegra/xusb.c +++ b/drivers/phy/tegra/xusb.c @@ -171,16 +171,16 @@ int tegra_xusb_pad_init(struct tegra_xusb_pad *pad, err = dev_set_name(&pad->dev, "%s", pad->soc->name); if (err < 0) - goto unregister; + goto put_device; err = device_add(&pad->dev); if (err < 0) - goto unregister; + goto put_device; return 0; -unregister: - device_unregister(&pad->dev); +put_device: + put_device(&pad->dev); return err; } -- 2.17.1

2 weeks, 1 day

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[PATCH] media: renesas: rcar_drif: fix device node reference leak in rcar_drif_bond_enabled

by Miaoqian Lin

The function calls of_parse_phandle() which returns a device node with an incremented reference count. When the bonded device is not available, the function returns NULL without releasing the reference, causing a reference leak. Add of_node_put(np) to release the device node reference. The of_node_put function handles NULL pointers. Found through static analysis by reviewing the doc of of_parse_phandle() and cross-checking its usage patterns across the codebase. Fixes: 7625ee981af1 ("[media] media: platform: rcar_drif: Add DRIF support") Cc: stable(a)vger.kernel.org Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com> --- drivers/media/platform/renesas/rcar_drif.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/media/platform/renesas/rcar_drif.c b/drivers/media/platform/renesas/rcar_drif.c index fc8b6bbef793..c5d676eb1091 100644 --- a/drivers/media/platform/renesas/rcar_drif.c +++ b/drivers/media/platform/renesas/rcar_drif.c @@ -1246,6 +1246,7 @@ static struct device_node *rcar_drif_bond_enabled(struct platform_device *p) if (np && of_device_is_available(np)) return np; + of_node_put(np); return NULL; } -- 2.35.1

2 weeks, 1 day

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Payment for Inv-1022

by Bergtrade®

2 weeks, 1 day

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[tip: perf/urgent] perf/core: Fix system hang caused by cpu-clock usage

by tip-bot2 for Dapeng Mi

The following commit has been merged into the perf/urgent branch of tip: Commit-ID: eb3182ef0405ff2f6668fd3e5ff9883f60ce8801 Gitweb: https://git.kernel.org/tip/eb3182ef0405ff2f6668fd3e5ff9883f60ce8801 Author: Dapeng Mi <dapeng1.mi(a)linux.intel.com> AuthorDate: Wed, 15 Oct 2025 13:18:28 +08:00 Committer: Ingo Molnar <mingo(a)kernel.org> CommitterDate: Mon, 03 Nov 2025 11:04:19 +01:00 perf/core: Fix system hang caused by cpu-clock usage cpu-clock usage by the async-profiler tool can trigger a system hang, which got bisected back to the following commit by Octavia Togami: 18dbcbfabfff ("perf: Fix the POLL_HUP delivery breakage") causes this issue The root cause of the hang is that cpu-clock is a special type of SW event which relies on hrtimers. The __perf_event_overflow() callback is invoked from the hrtimer handler for cpu-clock events, and __perf_event_overflow() tries to call cpu_clock_event_stop() to stop the event, which calls htimer_cancel() to cancel the hrtimer. But that's a recursion into the hrtimer code from a hrtimer handler, which (unsurprisingly) deadlocks. To fix this bug, use hrtimer_try_to_cancel() instead, and set the PERF_HES_STOPPED flag, which causes perf_swevent_hrtimer() to stop the event once it sees the PERF_HES_STOPPED flag. [ mingo: Fixed the comments and improved the changelog. ] Closes: https://lore.kernel.org/all/CAHPNGSQpXEopYreir+uDDEbtXTBvBvi8c6fYXJvceqtgTP… Fixes: 18dbcbfabfff ("perf: Fix the POLL_HUP delivery breakage") Reported-by: Octavia Togami <octavia.togami(a)gmail.com> Suggested-by: Peter Zijlstra <peterz(a)infradead.org> Signed-off-by: Dapeng Mi <dapeng1.mi(a)linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Tested-by: Octavia Togami <octavia.togami(a)gmail.com> Cc: stable(a)vger.kernel.org Link: https://github.com/lucko/spark/issues/530 Link: https://patch.msgid.link/20251015051828.12809-1-dapeng1.mi@linux.intel.com --- kernel/events/core.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 177e57c..1fd347d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11773,7 +11773,8 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) event = container_of(hrtimer, struct perf_event, hw.hrtimer); - if (event->state != PERF_EVENT_STATE_ACTIVE) + if (event->state != PERF_EVENT_STATE_ACTIVE || + event->hw.state & PERF_HES_STOPPED) return HRTIMER_NORESTART; event->pmu->read(event); @@ -11819,15 +11820,20 @@ static void perf_swevent_cancel_hrtimer(struct perf_event *event) struct hw_perf_event *hwc = &event->hw; /* - * The throttle can be triggered in the hrtimer handler. - * The HRTIMER_NORESTART should be used to stop the timer, - * rather than hrtimer_cancel(). See perf_swevent_hrtimer() + * Careful: this function can be triggered in the hrtimer handler, + * for cpu-clock events, so hrtimer_cancel() would cause a + * deadlock. + * + * So use hrtimer_try_to_cancel() to try to stop the hrtimer, + * and the cpu-clock handler also sets the PERF_HES_STOPPED flag, + * which guarantees that perf_swevent_hrtimer() will stop the + * hrtimer once it sees the PERF_HES_STOPPED flag. */ if (is_sampling_event(event) && (hwc->interrupts != MAX_INTERRUPTS)) { ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); local64_set(&hwc->period_left, ktime_to_ns(remaining)); - hrtimer_cancel(&hwc->hrtimer); + hrtimer_try_to_cancel(&hwc->hrtimer); } } @@ -11871,12 +11877,14 @@ static void cpu_clock_event_update(struct perf_event *event) static void cpu_clock_event_start(struct perf_event *event, int flags) { + event->hw.state = 0; local64_set(&event->hw.prev_count, local_clock()); perf_swevent_start_hrtimer(event); } static void cpu_clock_event_stop(struct perf_event *event, int flags) { + event->hw.state = PERF_HES_STOPPED; perf_swevent_cancel_hrtimer(event); if (flags & PERF_EF_UPDATE) cpu_clock_event_update(event); @@ -11950,12 +11958,14 @@ static void task_clock_event_update(struct perf_event *event, u64 now) static void task_clock_event_start(struct perf_event *event, int flags) { + event->hw.state = 0; local64_set(&event->hw.prev_count, event->ctx->time); perf_swevent_start_hrtimer(event); } static void task_clock_event_stop(struct perf_event *event, int flags) { + event->hw.state = PERF_HES_STOPPED; perf_swevent_cancel_hrtimer(event); if (flags & PERF_EF_UPDATE) task_clock_event_update(event, event->ctx->time);

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Re: [REGRESSION] bisected: perf: hang when using async-profiler caused by perf: Fix the POLL_HUP delivery breakage

by Harvey Tite

Hello hope everyone is well, just following up on this bug report, this appears to have been patched here https://lore.kernel.org/lkml/20251015051828.12809-1-dapeng1.mi@linux.intel.… thanks to Dapeng Mi; however, the patch email does not appear to have CCed the regressions or stable list. On 2025/10/15 Peter Zijlstra wrote: > So yeah, I suppose this works. Let me go queue this up. In regard to the patch, hence I assume the patch is approved for implementation in future versions. This is a critical bug causing widespread irrecoverable system freezes reported by many users with many differing setups, including myself. Notably it is being triggered by a minecraft mod called spark with at least 150 million aggregate downloads (https://www.curseforge.com/minecraft/mc-mods/spark https://github.com/lucko/spark/issues/530). If at all possible I would love to request that this please be implemented/backported to kernels 6.17 and 6.18. Thank you.

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