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[PATCH] iio: dac: ad3552r-hs: fix out-of-bound write in ad3552r_hs_write_data_source

by Miaoqian Lin

When simple_write_to_buffer() succeeds, it returns the number of bytes actually copied to the buffer, which may be less than the requested 'count' if the buffer size is insufficient. However, the current code incorrectly uses 'count' as the index for null termination instead of the actual bytes copied, leading to out-of-bound write. Add a check for the count and use the return value as the index. Found via static analysis. This is similar to the commit da9374819eb3 ("iio: backend: fix out-of-bound write") Fixes: b1c5d68ea66e ("iio: dac: ad3552r-hs: add support for internal ramp") Cc: stable(a)vger.kernel.org Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com> --- drivers/iio/dac/ad3552r-hs.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/iio/dac/ad3552r-hs.c b/drivers/iio/dac/ad3552r-hs.c index 41b96b48ba98..a9578afa7015 100644 --- a/drivers/iio/dac/ad3552r-hs.c +++ b/drivers/iio/dac/ad3552r-hs.c @@ -549,12 +549,15 @@ static ssize_t ad3552r_hs_write_data_source(struct file *f, guard(mutex)(&st->lock); + if (count >= sizeof(buf)) + return -ENOSPC; + ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, userbuf, count); if (ret < 0) return ret; - buf[count] = '\0'; + buf[ret] = '\0'; ret = match_string(dbgfs_attr_source, ARRAY_SIZE(dbgfs_attr_source), buf); -- 2.39.5 (Apple Git-154)

1 week

[PATCH v2] pmdomain: mtk-pm-domains: improve spinlock recursion fix in probe with correcting reference count

by Macpaul Lin

Remove scpsys_get_legacy_regmap(), replacing its usage with of_find_node_with_property(). Explicitly call of_node_get(np) before each of_find_node_with_property() to maintain correct node reference counting. The of_find_node_with_property() function "consumes" its input by calling of_node_put() internally, whether or not it finds a match. Currently, dev->of_node (np) is passed multiple times in sequence without incrementing its reference count, causing it to be decremented multiple times and risking early memory release. Adding of_node_get(np) before each call balances the reference count, preventing premature node release. Fixes: c1bac49fe91f ("pmdomains: mtk-pm-domains: Fix spinlock recursion in probe") Cc: Stable(a)vger.kernel.org Signed-off-by: Macpaul Lin <macpaul.lin(a)mediatek.com> Tested-by: Louis-Alexis Eyraud <louisalexis.eyraud(a)collabora.com> --- drivers/pmdomain/mediatek/mtk-pm-domains.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) Changes for v2: - Rewording commit message. - Add Fixes: and Tested-by: tag, thanks. diff --git a/drivers/pmdomain/mediatek/mtk-pm-domains.c b/drivers/pmdomain/mediatek/mtk-pm-domains.c index 80561d27f2b2..f64f24d520dd 100644 --- a/drivers/pmdomain/mediatek/mtk-pm-domains.c +++ b/drivers/pmdomain/mediatek/mtk-pm-domains.c @@ -984,18 +984,6 @@ static void scpsys_domain_cleanup(struct scpsys *scpsys) } } -static struct device_node *scpsys_get_legacy_regmap(struct device_node *np, const char *pn) -{ - struct device_node *local_node; - - for_each_child_of_node(np, local_node) { - if (of_property_present(local_node, pn)) - return local_node; - } - - return NULL; -} - static int scpsys_get_bus_protection_legacy(struct device *dev, struct scpsys *scpsys) { const u8 bp_blocks[3] = { @@ -1017,7 +1005,8 @@ static int scpsys_get_bus_protection_legacy(struct device *dev, struct scpsys *s * this makes it then possible to allocate the array of bus_prot * regmaps and convert all to the new style handling. */ - node = scpsys_get_legacy_regmap(np, "mediatek,infracfg"); + of_node_get(np); + node = of_find_node_with_property(np, "mediatek,infracfg"); if (node) { regmap[0] = syscon_regmap_lookup_by_phandle(node, "mediatek,infracfg"); of_node_put(node); @@ -1030,7 +1019,8 @@ static int scpsys_get_bus_protection_legacy(struct device *dev, struct scpsys *s regmap[0] = NULL; } - node = scpsys_get_legacy_regmap(np, "mediatek,smi"); + of_node_get(np); + node = of_find_node_with_property(np, "mediatek,smi"); if (node) { smi_np = of_parse_phandle(node, "mediatek,smi", 0); of_node_put(node); @@ -1048,7 +1038,8 @@ static int scpsys_get_bus_protection_legacy(struct device *dev, struct scpsys *s regmap[1] = NULL; } - node = scpsys_get_legacy_regmap(np, "mediatek,infracfg-nao"); + of_node_get(np); + node = of_find_node_with_property(np, "mediatek,infracfg-nao"); if (node) { regmap[2] = syscon_regmap_lookup_by_phandle(node, "mediatek,infracfg-nao"); num_regmaps++; -- 2.45.2

1 week

[PATCH v4] pmdomain: imx: Fix reference count leak in imx_gpc_probe()

by Wentao Liang

of_get_child_by_name() returns a node pointer with refcount incremented. Use the __free() attribute to manage the pgc_node reference, ensuring automatic of_node_put() cleanup when pgc_node goes out of scope. This eliminates the need for explicit error handling paths and avoids reference count leaks. Fixes: 721cabf6c660 ("soc: imx: move PGC handling to a new GPC driver") Cc: stable(a)vger.kernel.org Signed-off-by: Wentao Liang <vulab(a)iscas.ac.cn> --- Change in V4: - Fix typo error in code Change in V3: - Ensure variable is assigned when using cleanup attribute Change in V2: - Use __free() attribute instead of explicit of_node_put() calls --- drivers/pmdomain/imx/gpc.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/pmdomain/imx/gpc.c b/drivers/pmdomain/imx/gpc.c index f18c7e6e75dd..56a78cc86584 100644 --- a/drivers/pmdomain/imx/gpc.c +++ b/drivers/pmdomain/imx/gpc.c @@ -403,13 +403,12 @@ static int imx_gpc_old_dt_init(struct device *dev, struct regmap *regmap, static int imx_gpc_probe(struct platform_device *pdev) { const struct imx_gpc_dt_data *of_id_data = device_get_match_data(&pdev->dev); - struct device_node *pgc_node; + struct device_node *pgc_node __free(device_node) + = of_get_child_by_name(pdev->dev.of_node, "pgc"); struct regmap *regmap; void __iomem *base; int ret; - pgc_node = of_get_child_by_name(pdev->dev.of_node, "pgc"); - /* bail out if DT too old and doesn't provide the necessary info */ if (!of_property_present(pdev->dev.of_node, "#power-domain-cells") && !pgc_node) -- 2.34.1

1 week

[PATCH] soc: ti: pruss: fix double free in pruss_clk_mux_setup()

by Wentao Liang

In the pruss_clk_mux_setup(), the devm_add_action_or_reset() indirectly calls pruss_of_free_clk_provider(), which calls of_node_put(clk_mux_np) on the error path. However, after the devm_add_action_or_reset() returns, the of_node_put(clk_mux_np) is called again, causing a double free. Fix by using a separate label to avoid the duplicate of_node_put(). Fixes: ba59c9b43c86 ("soc: ti: pruss: support CORECLK_MUX and IEPCLK_MUX") Cc: stable(a)vger.kernel.org Signed-off-by: Wentao Liang <vulab(a)iscas.ac.cn> --- drivers/soc/ti/pruss.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c index d7634bf5413a..c16d96bebe3f 100644 --- a/drivers/soc/ti/pruss.c +++ b/drivers/soc/ti/pruss.c @@ -368,13 +368,14 @@ static int pruss_clk_mux_setup(struct pruss *pruss, struct clk *clk_mux, clk_mux_np); if (ret) { dev_err(dev, "failed to add clkmux free action %d", ret); - goto put_clk_mux_np; + goto ret_error; } return 0; put_clk_mux_np: of_node_put(clk_mux_np); +ret_error: return ret; } -- 2.34.1

1 week

[PATCH] phy: rockchip: inno-usb2: Fix a double free bug in rockchip_usb2phy_probe()

by Wentao Liang

The for_each_available_child_of_node() calls of_node_put() to release child_np in each success loop. After breaking from the loop with the child_np has been released, the code will jump to the put_child label and will call the of_node_put() again if the devm_request_threaded_irq() fails. These cause a double free bug. Fix by using a separate label to avoid the duplicate of_node_put(). Fixes: ed2b5a8e6b98 ("phy: phy-rockchip-inno-usb2: support muxed interrupts") Cc: stable(a)vger.kernel.org Signed-off-by: Wentao Liang <vulab(a)iscas.ac.cn> --- drivers/phy/rockchip/phy-rockchip-inno-usb2.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/phy/rockchip/phy-rockchip-inno-usb2.c b/drivers/phy/rockchip/phy-rockchip-inno-usb2.c index b0f23690ec30..f754c3b1c357 100644 --- a/drivers/phy/rockchip/phy-rockchip-inno-usb2.c +++ b/drivers/phy/rockchip/phy-rockchip-inno-usb2.c @@ -1491,7 +1491,7 @@ static int rockchip_usb2phy_probe(struct platform_device *pdev) rphy); if (ret) { dev_err_probe(rphy->dev, ret, "failed to request usb2phy irq handle\n"); - goto put_child; + goto ret_error; } } @@ -1499,6 +1499,7 @@ static int rockchip_usb2phy_probe(struct platform_device *pdev) put_child: of_node_put(child_np); +ret_error: return ret; } -- 2.34.1

1 week

[PATCH] w1: fix redundant counter decrement in w1_attach_slave_device()

by Haoxiang Li

In w1_attach_slave_device(), if __w1_attach_slave_device() fails, put_device() -> w1_slave_release() is called to do the cleanup job. In w1_slave_release(), sl->family->refcnt and sl->master->slave_count have already been decremented. There is no need to decrement twice in w1_attach_slave_device(). Fixes: 2c927c0c73fd ("w1: Fix slave count on 1-Wire bus (resend)") Cc: stable(a)vger.kernel.org Signed-off-by: Haoxiang Li <lihaoxiang(a)isrc.iscas.ac.cn> --- drivers/w1/w1.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 002d2639aa12..5f78b0a0b766 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -758,8 +758,6 @@ int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) if (err < 0) { dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__, sl->name); - dev->slave_count--; - w1_family_put(sl->family); atomic_dec(&sl->master->refcnt); kfree(sl); return err; -- 2.25.1

1 week

[PATCH v3 0/2] nfc: llcp: fix double put/unlock on LLCP_CLOSED in recv handlers

by Qianchang Zhao

Changes in v3: - Wrap commit messages to <= 75 columns - Use 12-char SHA in Fixes tags - Verify Fixes with git blame (both handlers trace back to d646960f7986) - Run scripts/checkpatch.pl --strict Qianchang Zhao (2): nfc: llcp: avoid double release/put on LLCP_CLOSED in nfc_llcp_recv_disc() nfc: llcp: stop processing on LLCP_CLOSED in nfc_llcp_recv_hdlc() net/nfc/llcp_core.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) -- 2.34.1

1 week

[PATCH v2] net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write

by Deepanshu Kartikey

A deadlock can occur between nfc_unregister_device() and rfkill_fop_write() due to lock ordering inversion between device_lock and rfkill_global_mutex. The problematic lock order is: Thread A (rfkill_fop_write): rfkill_fop_write() mutex_lock(&rfkill_global_mutex) rfkill_set_block() nfc_rfkill_set_block() nfc_dev_down() device_lock(&dev->dev) <- waits for device_lock Thread B (nfc_unregister_device): nfc_unregister_device() device_lock(&dev->dev) rfkill_unregister() mutex_lock(&rfkill_global_mutex) <- waits for rfkill_global_mutex This creates a classic ABBA deadlock scenario. Fix this by moving rfkill_unregister() and rfkill_destroy() outside the device_lock critical section. Store the rfkill pointer in a local variable before releasing the lock, then call rfkill_unregister() after releasing device_lock. This change is safe because rfkill_fop_write() holds rfkill_global_mutex while calling the rfkill callbacks, and rfkill_unregister() also acquires rfkill_global_mutex before cleanup. Therefore, rfkill_unregister() will wait for any ongoing callback to complete before proceeding, and device_del() is only called after rfkill_unregister() returns, preventing any use-after-free. The similar lock ordering in nfc_register_device() (device_lock -> rfkill_global_mutex via rfkill_register) is safe because during registration the device is not yet in rfkill_list, so no concurrent rfkill operations can occur on this device. Fixes: 3e3b5dfcd16a ("NFC: reorder the logic in nfc_{un,}register_device") Cc: stable(a)vger.kernel.org Reported-by: syzbot+4ef89409a235d804c6c2(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4ef89409a235d804c6c2 Link: https://lore.kernel.org/all/20251217054908.178907-1-kartikey406@gmail.com/T/ [v1] Signed-off-by: Deepanshu Kartikey <kartikey406(a)gmail.com> --- v2: - Added explanation of why UAF is not possible - Added explanation of why nfc_register_device() is safe - Added Fixes and Cc: stable tags - Fixed blank line after variable declaration (kept it) --- net/nfc/core.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/nfc/core.c b/net/nfc/core.c index ae1c842f9c64..82f023f37754 100644 --- a/net/nfc/core.c +++ b/net/nfc/core.c @@ -1154,6 +1154,7 @@ EXPORT_SYMBOL(nfc_register_device); void nfc_unregister_device(struct nfc_dev *dev) { int rc; + struct rfkill *rfk = NULL; pr_debug("dev_name=%s\n", dev_name(&dev->dev)); @@ -1164,13 +1165,17 @@ void nfc_unregister_device(struct nfc_dev *dev) device_lock(&dev->dev); if (dev->rfkill) { - rfkill_unregister(dev->rfkill); - rfkill_destroy(dev->rfkill); + rfk = dev->rfkill; dev->rfkill = NULL; } dev->shutting_down = true; device_unlock(&dev->dev); + if (rfk) { + rfkill_unregister(rfk); + rfkill_destroy(rfk); + } + if (dev->ops->check_presence) { timer_delete_sync(&dev->check_pres_timer); cancel_work_sync(&dev->check_pres_work); -- 2.43.0

1 week

[PATCH] arm64: errata: Workaround for SI L1 downstream coherency issue

by Lucas Wei

When software issues a Cache Maintenance Operation (CMO) targeting a dirty cache line, the CPU and DSU cluster may optimize the operation by combining the CopyBack Write and CMO into a single combined CopyBack Write plus CMO transaction presented to the interconnect (MCN). For these combined transactions, the MCN splits the operation into two separate transactions, one Write and one CMO, and then propagates the write and optionally the CMO to the downstream memory system or external Point of Serialization (PoS). However, the MCN may return an early CompCMO response to the DSU cluster before the corresponding Write and CMO transactions have completed at the external PoS or downstream memory. As a result, stale data may be observed by external observers that are directly connected to the external PoS or downstream memory. This erratum affects any system topology in which the following conditions apply: - The Point of Serialization (PoS) is located downstream of the interconnect. - A downstream observer accesses memory directly, bypassing the interconnect. Conditions: This erratum occurs only when all of the following conditions are met: 1. Software executes a data cache maintenance operation, specifically, a clean or invalidate by virtual address (DC CVAC, DC CIVAC, or DC IVAC), that hits on unique dirty data in the CPU or DSU cache. This results in a combined CopyBack and CMO being issued to the interconnect. 2. The interconnect splits the combined transaction into separate Write and CMO transactions and returns an early completion response to the CPU or DSU before the write has completed at the downstream memory or PoS. 3. A downstream observer accesses the affected memory address after the early completion response is issued but before the actual memory write has completed. This allows the observer to read stale data that has not yet been updated at the PoS or downstream memory. The implementation of workaround put a second loop of CMOs at the same virtual address whose operation meet erratum conditions to wait until cache data be cleaned to PoC.. This way of implementation mitigates performance panalty compared to purly duplicate orignial CMO. Cc: stable(a)vger.kernel.org # 6.12.x Signed-off-by: Lucas Wei <lucaswei(a)google.com> --- Documentation/arch/arm64/silicon-errata.rst | 3 ++ arch/arm64/Kconfig | 19 +++++++++++++ arch/arm64/include/asm/assembler.h | 10 +++++++ arch/arm64/kernel/cpu_errata.c | 31 +++++++++++++++++++++ arch/arm64/mm/cache.S | 13 ++++++++- arch/arm64/tools/cpucaps | 1 + 6 files changed, 76 insertions(+), 1 deletion(-) diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index a7ec57060f64..98efdf528719 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -213,6 +213,9 @@ stable kernels. | ARM | GIC-700 | #2941627 | ARM64_ERRATUM_2941627 | +----------------+-----------------+-----------------+-----------------------------+ +----------------+-----------------+-----------------+-----------------------------+ +| ARM | SI L1 | #4311569 | ARM64_ERRATUM_4311569 | ++----------------+-----------------+-----------------+-----------------------------+ ++----------------+-----------------+-----------------+-----------------------------+ | Broadcom | Brahma-B53 | N/A | ARM64_ERRATUM_845719 | +----------------+-----------------+-----------------+-----------------------------+ | Broadcom | Brahma-B53 | N/A | ARM64_ERRATUM_843419 | diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 93173f0a09c7..89326bb26f48 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1155,6 +1155,25 @@ config ARM64_ERRATUM_3194386 If unsure, say Y. +config ARM64_ERRATUM_4311569 + bool "SI L1: 4311569: workaround for premature CMO completion erratum" + default y + help + This option adds the workaround for ARM SI L1 erratum 4311569. + + The erratum of SI L1 can cause an early response to a combined write + and cache maintenance operation (WR+CMO) before the operation is fully + completed to the Point of Serialization (POS). + This can result in a non-I/O coherent agent observing stale data, + potentially leading to system instability or incorrect behavior. + + Enabling this option implements a software workaround by inserting a + second loop of Cache Maintenance Operation (CMO) immediately following the + end of function to do CMOs. This ensures that the data is correctly serialized + before the buffer is handed off to a non-coherent agent. + + If unsure, say Y. + config CAVIUM_ERRATUM_22375 bool "Cavium erratum 22375, 24313" default y diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index f0ca7196f6fa..d3d46e5f7188 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -381,6 +381,9 @@ alternative_endif .macro dcache_by_myline_op op, domain, start, end, linesz, tmp, fixup sub \tmp, \linesz, #1 bic \start, \start, \tmp +alternative_if ARM64_WORKAROUND_4311569 + mov \tmp, \start +alternative_else_nop_endif .Ldcache_op\@: .ifc \op, cvau __dcache_op_workaround_clean_cache \op, \start @@ -402,6 +405,13 @@ alternative_endif add \start, \start, \linesz cmp \start, \end b.lo .Ldcache_op\@ +alternative_if ARM64_WORKAROUND_4311569 + .ifnc \op, cvau + mov \start, \tmp + mov \tmp, xzr + cbnz \start, .Ldcache_op\@ + .endif +alternative_else_nop_endif dsb \domain _cond_uaccess_extable .Ldcache_op\@, \fixup diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 8cb3b575a031..c69678c512f1 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -141,6 +141,30 @@ has_mismatched_cache_type(const struct arm64_cpu_capabilities *entry, return (ctr_real != sys) && (ctr_raw != sys); } +#ifdef CONFIG_ARM64_ERRATUM_4311569 +DEFINE_STATIC_KEY_FALSE(arm_si_l1_workaround_4311569); +static int __init early_arm_si_l1_workaround_4311569_cfg(char *arg) +{ + static_branch_enable(&arm_si_l1_workaround_4311569); + pr_info("Enabling cache maintenance workaround for ARM SI-L1 erratum 4311569\n"); + + return 0; +} +early_param("arm_si_l1_workaround_4311569", early_arm_si_l1_workaround_4311569_cfg); + +/* + * We have some earlier use cases to call cache maintenance operation functions, for example, + * dcache_inval_poc() and dcache_clean_poc() in head.S, before making decision to turn on this + * workaround. Since the scope of this workaround is limited to non-coherent DMA agents, its + * safe to have the workaround off by default. + */ +static bool +need_arm_si_l1_workaround_4311569(const struct arm64_cpu_capabilities *entry, int scope) +{ + return static_branch_unlikely(&arm_si_l1_workaround_4311569); +} +#endif + static void cpu_enable_trap_ctr_access(const struct arm64_cpu_capabilities *cap) { @@ -870,6 +894,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = { ERRATA_MIDR_RANGE_LIST(erratum_spec_ssbs_list), }, #endif +#ifdef CONFIG_ARM64_ERRATUM_4311569 + { + .capability = ARM64_WORKAROUND_4311569, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = need_arm_si_l1_workaround_4311569, + }, +#endif #ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD { .desc = "ARM errata 2966298, 3117295", diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S index 503567c864fd..ddf0097624ed 100644 --- a/arch/arm64/mm/cache.S +++ b/arch/arm64/mm/cache.S @@ -143,9 +143,14 @@ SYM_FUNC_END(dcache_clean_pou) * - end - kernel end address of region */ SYM_FUNC_START(__pi_dcache_inval_poc) +alternative_if ARM64_WORKAROUND_4311569 + mov x4, x0 + mov x5, x1 + mov x6, #1 +alternative_else_nop_endif dcache_line_size x2, x3 sub x3, x2, #1 - tst x1, x3 // end cache line aligned? +again: tst x1, x3 // end cache line aligned? bic x1, x1, x3 b.eq 1f dc civac, x1 // clean & invalidate D / U line @@ -158,6 +163,12 @@ SYM_FUNC_START(__pi_dcache_inval_poc) 3: add x0, x0, x2 cmp x0, x1 b.lo 2b +alternative_if ARM64_WORKAROUND_4311569 + mov x0, x4 + mov x1, x5 + sub x6, x6, #1 + cbz x6, again +alternative_else_nop_endif dsb sy ret SYM_FUNC_END(__pi_dcache_inval_poc) diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 0fac75f01534..856b6cf6e71e 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -103,6 +103,7 @@ WORKAROUND_2077057 WORKAROUND_2457168 WORKAROUND_2645198 WORKAROUND_2658417 +WORKAROUND_4311569 WORKAROUND_AMPERE_AC03_CPU_38 WORKAROUND_AMPERE_AC04_CPU_23 WORKAROUND_TRBE_OVERWRITE_FILL_MODE -- 2.52.0.358.g0dd7633a29-goog

1 week, 1 day

[PATCH] powerpc/kexec: Enable SMT before waking offline CPUs

by Nysal Jan K.A.

If SMT is disabled or a partial SMT state is enabled, when a new kernel image is loaded for kexec, on reboot the following warning is observed: kexec: Waking offline cpu 228. WARNING: CPU: 0 PID: 9062 at arch/powerpc/kexec/core_64.c:223 kexec_prepare_cpus+0x1b0/0x1bc [snip] NIP kexec_prepare_cpus+0x1b0/0x1bc LR kexec_prepare_cpus+0x1a0/0x1bc Call Trace: kexec_prepare_cpus+0x1a0/0x1bc (unreliable) default_machine_kexec+0x160/0x19c machine_kexec+0x80/0x88 kernel_kexec+0xd0/0x118 __do_sys_reboot+0x210/0x2c4 system_call_exception+0x124/0x320 system_call_vectored_common+0x15c/0x2ec This occurs as add_cpu() fails due to cpu_bootable() returning false for CPUs that fail the cpu_smt_thread_allowed() check or non primary threads if SMT is disabled. Fix the issue by enabling SMT and resetting the number of SMT threads to the number of threads per core, before attempting to wake up all present CPUs. Fixes: 38253464bc82 ("cpu/SMT: Create topology_smt_thread_allowed()") Reported-by: Sachin P Bappalige <sachinpb(a)linux.ibm.com> Cc: stable(a)vger.kernel.org # v6.6+ Signed-off-by: Nysal Jan K.A. <nysal(a)linux.ibm.com> --- arch/powerpc/kexec/core_64.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c index 222aa326dace..ff6df43720c4 100644 --- a/arch/powerpc/kexec/core_64.c +++ b/arch/powerpc/kexec/core_64.c @@ -216,6 +216,11 @@ static void wake_offline_cpus(void) { int cpu = 0; + lock_device_hotplug(); + cpu_smt_num_threads = threads_per_core; + cpu_smt_control = CPU_SMT_ENABLED; + unlock_device_hotplug(); + for_each_present_cpu(cpu) { if (!cpu_online(cpu)) { printk(KERN_INFO "kexec: Waking offline cpu %d.\n", -- 2.51.0

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