- Linux-stable-mirror - lists.linaro.org

[PATCH 4.19 1/3] x86/resctrl: Fix use-after-free when deleting resource groups

by Xiaochen Shen

commit b8511ccc75c033f6d54188ea4df7bf1e85778740 upstream. A resource group (rdtgrp) contains a reference count (rdtgrp->waitcount) that indicates how many waiters expect this rdtgrp to exist. Waiters could be waiting on rdtgroup_mutex or some work sitting on a task's workqueue for when the task returns from kernel mode or exits. The deletion of a rdtgrp is intended to have two phases: (1) while holding rdtgroup_mutex the necessary cleanup is done and rdtgrp->flags is set to RDT_DELETED, (2) after releasing the rdtgroup_mutex, the rdtgrp structure is freed only if there are no waiters and its flag is set to RDT_DELETED. Upon gaining access to rdtgroup_mutex or rdtgrp, a waiter is required to check for the RDT_DELETED flag. When unmounting the resctrl file system or deleting ctrl_mon groups, all of the subdirectories are removed and the data structure of rdtgrp is forcibly freed without checking rdtgrp->waitcount. If at this point there was a waiter on rdtgrp then a use-after-free issue occurs when the waiter starts running and accesses the rdtgrp structure it was waiting on. See kfree() calls in [1], [2] and [3] in these two call paths in following scenarios: (1) rdt_kill_sb() -> rmdir_all_sub() -> free_all_child_rdtgrp() (2) rdtgroup_rmdir() -> rdtgroup_rmdir_ctrl() -> free_all_child_rdtgrp() There are several scenarios that result in use-after-free issue in following: Scenario 1: ----------- In Thread 1, rdtgroup_tasks_write() adds a task_work callback move_myself(). If move_myself() is scheduled to execute after Thread 2 rdt_kill_sb() is finished, referring to earlier rdtgrp memory (rdtgrp->waitcount) which was already freed in Thread 2 results in use-after-free issue. Thread 1 (rdtgroup_tasks_write) Thread 2 (rdt_kill_sb) ------------------------------- ---------------------- rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) mutex_lock rdtgroup_move_task __rdtgroup_move_task /* * Take an extra refcount, so rdtgrp cannot be freed * before the call back move_myself has been invoked */ atomic_inc(&rdtgrp->waitcount) /* Callback move_myself will be scheduled for later */ task_work_add(move_myself) rdtgroup_kn_unlock mutex_unlock atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) mutex_lock rmdir_all_sub /* * sentry and rdtgrp are freed * without checking refcount */ free_all_child_rdtgrp kfree(sentry)*[1] kfree(rdtgrp)*[2] mutex_unlock /* * Callback is scheduled to execute * after rdt_kill_sb is finished */ move_myself /* * Use-after-free: refer to earlier rdtgrp * memory which was freed in [1] or [2]. */ atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) kfree(rdtgrp) Scenario 2: ----------- In Thread 1, rdtgroup_tasks_write() adds a task_work callback move_myself(). If move_myself() is scheduled to execute after Thread 2 rdtgroup_rmdir() is finished, referring to earlier rdtgrp memory (rdtgrp->waitcount) which was already freed in Thread 2 results in use-after-free issue. Thread 1 (rdtgroup_tasks_write) Thread 2 (rdtgroup_rmdir) ------------------------------- ------------------------- rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) mutex_lock rdtgroup_move_task __rdtgroup_move_task /* * Take an extra refcount, so rdtgrp cannot be freed * before the call back move_myself has been invoked */ atomic_inc(&rdtgrp->waitcount) /* Callback move_myself will be scheduled for later */ task_work_add(move_myself) rdtgroup_kn_unlock mutex_unlock atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) mutex_lock rdtgroup_rmdir_ctrl free_all_child_rdtgrp /* * sentry is freed without * checking refcount */ kfree(sentry)*[3] rdtgroup_ctrl_remove rdtgrp->flags = RDT_DELETED rdtgroup_kn_unlock mutex_unlock atomic_dec_and_test( &rdtgrp->waitcount) && (flags & RDT_DELETED) kfree(rdtgrp) /* * Callback is scheduled to execute * after rdt_kill_sb is finished */ move_myself /* * Use-after-free: refer to earlier rdtgrp * memory which was freed in [3]. */ atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) kfree(rdtgrp) If CONFIG_DEBUG_SLAB=y, Slab corruption on kmalloc-2k can be observed like following. Note that "0x6b" is POISON_FREE after kfree(). The corrupted bits "0x6a", "0x64" at offset 0x424 correspond to waitcount member of struct rdtgroup which was freed: Slab corruption (Not tainted): kmalloc-2k start=ffff9504c5b0d000, len=2048 420: 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkjkkkkkkkkkkk Single bit error detected. Probably bad RAM. Run memtest86+ or a similar memory test tool. Next obj: start=ffff9504c5b0d800, len=2048 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Slab corruption (Not tainted): kmalloc-2k start=ffff9504c58ab800, len=2048 420: 6b 6b 6b 6b 64 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkdkkkkkkkkkkk Prev obj: start=ffff9504c58ab000, len=2048 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Fix this by taking reference count (waitcount) of rdtgrp into account in the two call paths that currently do not do so. Instead of always freeing the resource group it will only be freed if there are no waiters on it. If there are waiters, the resource group will have its flags set to RDT_DELETED. It will be left to the waiter to free the resource group when it starts running and finding that it was the last waiter and the resource group has been removed (rdtgrp->flags & RDT_DELETED) since. (1) rdt_kill_sb() -> rmdir_all_sub() -> free_all_child_rdtgrp() (2) rdtgroup_rmdir() -> rdtgroup_rmdir_ctrl() -> free_all_child_rdtgrp() Backporting notes: Since upstream commit fa7d949337cc ("x86/resctrl: Rename and move rdt files to a separate directory"), the file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c has been renamed and moved to arch/x86/kernel/cpu/resctrl/rdtgroup.c. Apply the change against file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c in older stable trees. Fixes: f3cbeacaa06e ("x86/intel_rdt/cqm: Add rmdir support") Fixes: 60cf5e101fd4 ("x86/intel_rdt: Add mkdir to resctrl file system") Suggested-by: Reinette Chatre <reinette.chatre(a)intel.com> Signed-off-by: Xiaochen Shen <xiaochen.shen(a)intel.com> Signed-off-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> Reviewed-by: Tony Luck <tony.luck(a)intel.com> Acked-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Link: https://lkml.kernel.org/r/1578500886-21771-2-git-send-email-xiaochen.shen@i… --- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 841a024..db22ba0 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -2167,7 +2167,11 @@ static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp) list_for_each_entry_safe(sentry, stmp, head, mon.crdtgrp_list) { free_rmid(sentry->mon.rmid); list_del(&sentry->mon.crdtgrp_list); - kfree(sentry); + + if (atomic_read(&sentry->waitcount) != 0) + sentry->flags = RDT_DELETED; + else + kfree(sentry); } } @@ -2205,7 +2209,11 @@ static void rmdir_all_sub(void) kernfs_remove(rdtgrp->kn); list_del(&rdtgrp->rdtgroup_list); - kfree(rdtgrp); + + if (atomic_read(&rdtgrp->waitcount) != 0) + rdtgrp->flags = RDT_DELETED; + else + kfree(rdtgrp); } /* Notify online CPUs to update per cpu storage and PQR_ASSOC MSR */ update_closid_rmid(cpu_online_mask, &rdtgroup_default); -- 1.8.3.1

5 years, 9 months

2
1
0 0

[PATCH] drm: Remove PageReserved manipulation from drm_pci_alloc

by Chris Wilson

drm_pci_alloc/drm_pci_free are very thin wrappers around the core dma facilities, and we have no special reason within the drm layer to behave differently. In particular, since commit de09d31dd38a50fdce106c15abd68432eebbd014 Author: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Date: Fri Jan 15 16:51:42 2016 -0800 page-flags: define PG_reserved behavior on compound pages As far as I can see there's no users of PG_reserved on compound pages. Let's use PF_NO_COMPOUND here. it has been illegal to combine GFP_COMP with SetPageReserved, so lets stop doing both and leave the dma layer to its own devices. Reported-by: Taketo Kabe Closes: https://gitlab.freedesktop.org/drm/intel/issues/1027 Fixes: de09d31dd38a ("page-flags: define PG_reserved behavior on compound pages") Signed-off-by: Chris Wilson <chris(a)chris-wilson.co.uk> Cc: <stable(a)vger.kernel.org> # v4.5+ --- drivers/gpu/drm/drm_pci.c | 23 ++--------------------- 1 file changed, 2 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c index f2e43d341980..d16dac4325f9 100644 --- a/drivers/gpu/drm/drm_pci.c +++ b/drivers/gpu/drm/drm_pci.c @@ -51,8 +51,6 @@ drm_dma_handle_t *drm_pci_alloc(struct drm_device * dev, size_t size, size_t align) { drm_dma_handle_t *dmah; - unsigned long addr; - size_t sz; /* pci_alloc_consistent only guarantees alignment to the smallest * PAGE_SIZE order which is greater than or equal to the requested size. @@ -68,20 +66,13 @@ drm_dma_handle_t *drm_pci_alloc(struct drm_device * dev, size_t size, size_t ali dmah->size = size; dmah->vaddr = dma_alloc_coherent(&dev->pdev->dev, size, &dmah->busaddr, - GFP_KERNEL | __GFP_COMP); + GFP_KERNEL); if (dmah->vaddr == NULL) { kfree(dmah); return NULL; } - /* XXX - Is virt_to_page() legal for consistent mem? */ - /* Reserve */ - for (addr = (unsigned long)dmah->vaddr, sz = size; - sz > 0; addr += PAGE_SIZE, sz -= PAGE_SIZE) { - SetPageReserved(virt_to_page((void *)addr)); - } - return dmah; } @@ -94,19 +85,9 @@ EXPORT_SYMBOL(drm_pci_alloc); */ void __drm_legacy_pci_free(struct drm_device * dev, drm_dma_handle_t * dmah) { - unsigned long addr; - size_t sz; - - if (dmah->vaddr) { - /* XXX - Is virt_to_page() legal for consistent mem? */ - /* Unreserve */ - for (addr = (unsigned long)dmah->vaddr, sz = dmah->size; - sz > 0; addr += PAGE_SIZE, sz -= PAGE_SIZE) { - ClearPageReserved(virt_to_page((void *)addr)); - } + if (dmah->vaddr) dma_free_coherent(&dev->pdev->dev, dmah->size, dmah->vaddr, dmah->busaddr); - } } /** -- 2.25.0

5 years, 9 months

2
2
0 0

[PATCH] drm/i915: Wean off drm_pci_alloc/drm_pci_free

by Chris Wilson

drm_pci_alloc and drm_pci_free are just very thin wrappers around dma_alloc_coherent, with a note that we should be removing them. Furthermore since commit de09d31dd38a50fdce106c15abd68432eebbd014 Author: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Date: Fri Jan 15 16:51:42 2016 -0800 page-flags: define PG_reserved behavior on compound pages As far as I can see there's no users of PG_reserved on compound pages. Let's use PF_NO_COMPOUND here. drm_pci_alloc has been declared broken since it mixes GFP_COMP and SetPageReserved. Avoid this conflict by weaning ourselves off using the abstraction and using the dma functions directly. Reported-by: Taketo Kabe Closes: https://gitlab.freedesktop.org/drm/intel/issues/1027 Fixes: de09d31dd38a ("page-flags: define PG_reserved behavior on compound pages") Signed-off-by: Chris Wilson <chris(a)chris-wilson.co.uk> Cc: <stable(a)vger.kernel.org> # v4.5+ --- drivers/gpu/drm/i915/display/intel_display.c | 2 +- .../gpu/drm/i915/gem/i915_gem_object_types.h | 3 - drivers/gpu/drm/i915/gem/i915_gem_phys.c | 98 ++++++++++--------- drivers/gpu/drm/i915/i915_gem.c | 8 +- 4 files changed, 55 insertions(+), 56 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index b0af37fb6d4a..1f584263aa97 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -11234,7 +11234,7 @@ static u32 intel_cursor_base(const struct intel_plane_state *plane_state) u32 base; if (INTEL_INFO(dev_priv)->display.cursor_needs_physical) - base = obj->phys_handle->busaddr; + base = sg_dma_address(obj->mm.pages->sgl); else base = intel_plane_ggtt_offset(plane_state); diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h index f64ad77e6b1e..c2174da35bb0 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h @@ -285,9 +285,6 @@ struct drm_i915_gem_object { void *gvt_info; }; - - /** for phys allocated objects */ - struct drm_dma_handle *phys_handle; }; static inline struct drm_i915_gem_object * diff --git a/drivers/gpu/drm/i915/gem/i915_gem_phys.c b/drivers/gpu/drm/i915/gem/i915_gem_phys.c index b1b7c1b3038a..b07bb40edd5a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_phys.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_phys.c @@ -22,88 +22,87 @@ static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj) { struct address_space *mapping = obj->base.filp->f_mapping; - struct drm_dma_handle *phys; - struct sg_table *st; struct scatterlist *sg; - char *vaddr; + struct sg_table *st; + dma_addr_t dma; + void *vaddr; + void *dst; int i; - int err; if (WARN_ON(i915_gem_object_needs_bit17_swizzle(obj))) return -EINVAL; - /* Always aligning to the object size, allows a single allocation + /* + * Always aligning to the object size, allows a single allocation * to handle all possible callers, and given typical object sizes, * the alignment of the buddy allocation will naturally match. */ - phys = drm_pci_alloc(obj->base.dev, - roundup_pow_of_two(obj->base.size), - roundup_pow_of_two(obj->base.size)); - if (!phys) + vaddr = dma_alloc_coherent(&obj->base.dev->pdev->dev, + roundup_pow_of_two(obj->base.size), + &dma, GFP_KERNEL); + if (!vaddr) return -ENOMEM; - vaddr = phys->vaddr; + st = kmalloc(sizeof(*st), GFP_KERNEL); + if (!st) + goto err_pci; + + if (sg_alloc_table(st, 1, GFP_KERNEL)) + goto err_st; + + sg = st->sgl; + sg->offset = 0; + sg->length = obj->base.size; + + sg_assign_page(sg, (struct page *)vaddr); + sg_dma_address(sg) = dma; + sg_dma_len(sg) = obj->base.size; + + dst = vaddr; for (i = 0; i < obj->base.size / PAGE_SIZE; i++) { struct page *page; - char *src; + void *src; page = shmem_read_mapping_page(mapping, i); - if (IS_ERR(page)) { - err = PTR_ERR(page); - goto err_phys; - } + if (IS_ERR(page)) + goto err_st; src = kmap_atomic(page); - memcpy(vaddr, src, PAGE_SIZE); - drm_clflush_virt_range(vaddr, PAGE_SIZE); + memcpy(dst, src, PAGE_SIZE); + drm_clflush_virt_range(dst, PAGE_SIZE); kunmap_atomic(src); put_page(page); - vaddr += PAGE_SIZE; + dst += PAGE_SIZE; } intel_gt_chipset_flush(&to_i915(obj->base.dev)->gt); - st = kmalloc(sizeof(*st), GFP_KERNEL); - if (!st) { - err = -ENOMEM; - goto err_phys; - } - - if (sg_alloc_table(st, 1, GFP_KERNEL)) { - kfree(st); - err = -ENOMEM; - goto err_phys; - } - - sg = st->sgl; - sg->offset = 0; - sg->length = obj->base.size; - - sg_dma_address(sg) = phys->busaddr; - sg_dma_len(sg) = obj->base.size; - - obj->phys_handle = phys; - __i915_gem_object_set_pages(obj, st, sg->length); return 0; -err_phys: - drm_pci_free(obj->base.dev, phys); - - return err; +err_st: + kfree(st); +err_pci: + dma_free_coherent(&obj->base.dev->pdev->dev, + roundup_pow_of_two(obj->base.size), + vaddr, dma); + return -ENOMEM; } static void i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj, struct sg_table *pages) { + dma_addr_t dma = sg_dma_address(pages->sgl); + void *vaddr = sg_page(pages->sgl); + __i915_gem_object_release_shmem(obj, pages, false); if (obj->mm.dirty) { struct address_space *mapping = obj->base.filp->f_mapping; - char *vaddr = obj->phys_handle->vaddr; + void *src = vaddr; int i; for (i = 0; i < obj->base.size / PAGE_SIZE; i++) { @@ -115,15 +114,16 @@ i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj, continue; dst = kmap_atomic(page); - drm_clflush_virt_range(vaddr, PAGE_SIZE); - memcpy(dst, vaddr, PAGE_SIZE); + drm_clflush_virt_range(src, PAGE_SIZE); + memcpy(dst, src, PAGE_SIZE); kunmap_atomic(dst); set_page_dirty(page); if (obj->mm.madv == I915_MADV_WILLNEED) mark_page_accessed(page); put_page(page); - vaddr += PAGE_SIZE; + + src += PAGE_SIZE; } obj->mm.dirty = false; } @@ -131,7 +131,9 @@ i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj, sg_free_table(pages); kfree(pages); - drm_pci_free(obj->base.dev, obj->phys_handle); + dma_free_coherent(&obj->base.dev->pdev->dev, + roundup_pow_of_two(obj->base.size), + vaddr, dma); } static void phys_release(struct drm_i915_gem_object *obj) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 7245e056ce77..a712e60b016a 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -180,7 +180,7 @@ i915_gem_phys_pwrite(struct drm_i915_gem_object *obj, struct drm_i915_gem_pwrite *args, struct drm_file *file) { - void *vaddr = obj->phys_handle->vaddr + args->offset; + void *vaddr = sg_page(obj->mm.pages->sgl) + args->offset; char __user *user_data = u64_to_user_ptr(args->data_ptr); /* @@ -844,10 +844,10 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data, ret = i915_gem_gtt_pwrite_fast(obj, args); if (ret == -EFAULT || ret == -ENOSPC) { - if (obj->phys_handle) - ret = i915_gem_phys_pwrite(obj, args, file); - else + if (i915_gem_object_has_struct_page(obj)) ret = i915_gem_shmem_pwrite(obj, args); + else + ret = i915_gem_phys_pwrite(obj, args, file); } i915_gem_object_unpin_pages(obj); -- 2.25.0

5 years, 9 months

2
1
0 0

Re: KASAN: use-after-free Read in snd_timer_resolution

by syzbot

syzbot has found a reproducer for the following crash on: HEAD commit: 2747d5fd Add linux-next specific files for 20200116 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=1147e101e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=22f506e7a3a37fe2 dashboard link: https://syzkaller.appspot.com/bug?extid=2b2ef983f973e5c40943 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10c0864ee00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14738df1e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+2b2ef983f973e5c40943(a)syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in snd_timer_resolution+0xf1/0x110 sound/core/timer.c:487 Read of size 8 at addr ffff88809e0f5a00 by task syz-executor911/9849 CPU: 1 PID: 9849 Comm: syz-executor911 Not tainted 5.5.0-rc6-next-20200116-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 snd_timer_resolution+0xf1/0x110 sound/core/timer.c:487 snd_seq_info_timer_read+0x95/0x2f1 sound/core/seq/seq_timer.c:480 snd_info_seq_show+0xcb/0x120 sound/core/info.c:362 seq_read+0x4ca/0x1170 fs/seq_file.c:229 proc_reg_read+0x1f8/0x2b0 fs/proc/inode.c:223 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_preadv+0x1c4/0x280 fs/read_write.c:1089 __do_sys_preadv fs/read_write.c:1139 [inline] __se_sys_preadv fs/read_write.c:1134 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1134 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441389 Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc8aa7ce38 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441389 RDX: 0000000000000227 RSI: 00000000200017c0 RDI: 0000000000000004 RBP: 00007ffc8aa7ce50 R08: 000000000000000f R09: 00000000000000c2 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402100 R13: 0000000000402190 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 9852: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:515 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] snd_timer_instance_new+0x4a/0x300 sound/core/timer.c:142 snd_seq_timer_open+0x1c0/0x590 sound/core/seq/seq_timer.c:275 queue_use+0xf1/0x270 sound/core/seq/seq_queue.c:489 snd_seq_queue_alloc+0x2c5/0x4d0 sound/core/seq/seq_queue.c:176 snd_seq_ioctl_create_queue+0xb0/0x330 sound/core/seq/seq_clientmgr.c:1548 snd_seq_kernel_client_ctl+0xf8/0x140 sound/core/seq/seq_clientmgr.c:2353 alloc_seq_queue.isra.0+0xdc/0x180 sound/core/seq/oss/seq_oss_init.c:357 snd_seq_oss_open+0x2ff/0x960 sound/core/seq/oss/seq_oss_init.c:215 odev_open+0x70/0x90 sound/core/seq/oss/seq_oss.c:125 soundcore_open+0x453/0x610 sound/sound_core.c:593 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4ca/0x1350 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3487 [inline] path_openat+0x12fd/0x34d0 fs/namei.c:3604 do_filp_open+0x192/0x260 fs/namei.c:3634 do_sys_openat2+0x633/0x840 fs/open.c:1151 do_sys_open+0xfc/0x190 fs/open.c:1167 __do_sys_openat fs/open.c:1181 [inline] __se_sys_openat fs/open.c:1176 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1176 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9852: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 snd_timer_instance_free sound/core/timer.c:166 [inline] snd_timer_instance_free+0x7c/0xa0 sound/core/timer.c:160 snd_seq_timer_close+0x99/0xe0 sound/core/seq/seq_timer.c:319 queue_delete+0x52/0xb0 sound/core/seq/seq_queue.c:134 snd_seq_queue_delete+0x4e/0x70 sound/core/seq/seq_queue.c:196 snd_seq_ioctl_delete_queue+0x6a/0x90 sound/core/seq/seq_clientmgr.c:1570 snd_seq_kernel_client_ctl+0xf8/0x140 sound/core/seq/seq_clientmgr.c:2353 delete_seq_queue.part.0+0xb6/0x120 sound/core/seq/oss/seq_oss_init.c:376 delete_seq_queue sound/core/seq/oss/seq_oss_init.c:372 [inline] snd_seq_oss_release+0x116/0x150 sound/core/seq/oss/seq_oss_init.c:421 odev_release+0x54/0x80 sound/core/seq/oss/seq_oss.c:140 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xbcb/0x2f80 kernel/exit.c:801 do_group_exit+0x135/0x360 kernel/exit.c:899 __do_sys_exit_group kernel/exit.c:910 [inline] __se_sys_exit_group kernel/exit.c:908 [inline] __x64_sys_exit_group+0x44/0x50 kernel/exit.c:908 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809e0f5a00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 0 bytes inside of 256-byte region [ffff88809e0f5a00, ffff88809e0f5b00) The buggy address belongs to the page: page:ffffea0002783d40 refcount:1 mapcount:0 mapping:ffff8880aa4008c0 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002783948 ffffea00027872c8 ffff8880aa4008c0 raw: 0000000000000000 ffff88809e0f5000 0000000100000008 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809e0f5900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809e0f5980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809e0f5a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809e0f5a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809e0f5b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================

5 years, 9 months

1
0
0 0

[PATCH] Revert "ASoC: tegra: Allow 24bit and 32bit samples"

by Jon Hunter

Commit f3ee99087c8ca0ecfdd549ef5a94f557c42d5428 ("ASoC: tegra: Allow 24bit and 32bit samples") added 24-bit and 32-bit support for to the Tegra30 I2S driver. However, there are two additional commits that are also needed to get 24-bit and 32-bit support to work correctly. These commits are not yet applied because there are still some review comments that need to be addressed. With only this change applied, 24-bit and 32-bit support is advertised by the I2S driver, but it does not work and the audio is distorted. Therefore, revert this patch for now until the other changes are also ready. Furthermore, a clock issue with 24-bit support has been identified with this change and so if we revert this now, we can also fix that in the updated version. Cc: stable(a)vger.kernel.org Reported-by: Dmitry Osipenko <digetx(a)gmail.com> Signed-off-by: Jon Hunter <jonathanh(a)nvidia.com> --- sound/soc/tegra/tegra30_i2s.c | 25 +++++-------------------- 1 file changed, 5 insertions(+), 20 deletions(-) diff --git a/sound/soc/tegra/tegra30_i2s.c b/sound/soc/tegra/tegra30_i2s.c index dbed3c5408e7..d59882ec48f1 100644 --- a/sound/soc/tegra/tegra30_i2s.c +++ b/sound/soc/tegra/tegra30_i2s.c @@ -127,7 +127,7 @@ static int tegra30_i2s_hw_params(struct snd_pcm_substream *substream, struct device *dev = dai->dev; struct tegra30_i2s *i2s = snd_soc_dai_get_drvdata(dai); unsigned int mask, val, reg; - int ret, sample_size, srate, i2sclock, bitcnt, audio_bits; + int ret, sample_size, srate, i2sclock, bitcnt; struct tegra30_ahub_cif_conf cif_conf; if (params_channels(params) != 2) @@ -137,19 +137,8 @@ static int tegra30_i2s_hw_params(struct snd_pcm_substream *substream, switch (params_format(params)) { case SNDRV_PCM_FORMAT_S16_LE: val = TEGRA30_I2S_CTRL_BIT_SIZE_16; - audio_bits = TEGRA30_AUDIOCIF_BITS_16; sample_size = 16; break; - case SNDRV_PCM_FORMAT_S24_LE: - val = TEGRA30_I2S_CTRL_BIT_SIZE_24; - audio_bits = TEGRA30_AUDIOCIF_BITS_24; - sample_size = 24; - break; - case SNDRV_PCM_FORMAT_S32_LE: - val = TEGRA30_I2S_CTRL_BIT_SIZE_32; - audio_bits = TEGRA30_AUDIOCIF_BITS_32; - sample_size = 32; - break; default: return -EINVAL; } @@ -181,8 +170,8 @@ static int tegra30_i2s_hw_params(struct snd_pcm_substream *substream, cif_conf.threshold = 0; cif_conf.audio_channels = 2; cif_conf.client_channels = 2; - cif_conf.audio_bits = audio_bits; - cif_conf.client_bits = audio_bits; + cif_conf.audio_bits = TEGRA30_AUDIOCIF_BITS_16; + cif_conf.client_bits = TEGRA30_AUDIOCIF_BITS_16; cif_conf.expand = 0; cif_conf.stereo_conv = 0; cif_conf.replicate = 0; @@ -317,18 +306,14 @@ static const struct snd_soc_dai_driver tegra30_i2s_dai_template = { .channels_min = 2, .channels_max = 2, .rates = SNDRV_PCM_RATE_8000_96000, - .formats = SNDRV_PCM_FMTBIT_S32_LE | - SNDRV_PCM_FMTBIT_S24_LE | - SNDRV_PCM_FMTBIT_S16_LE, + .formats = SNDRV_PCM_FMTBIT_S16_LE, }, .capture = { .stream_name = "Capture", .channels_min = 2, .channels_max = 2, .rates = SNDRV_PCM_RATE_8000_96000, - .formats = SNDRV_PCM_FMTBIT_S32_LE | - SNDRV_PCM_FMTBIT_S24_LE | - SNDRV_PCM_FMTBIT_S16_LE, + .formats = SNDRV_PCM_FMTBIT_S16_LE, }, .ops = &tegra30_i2s_dai_ops, .symmetric_rates = 1, -- 2.17.1

5 years, 9 months

3
4
0 0

[PATCH 4.19 3/3] x86/resctrl: Fix a deadlock due to inaccurate reference

by Xiaochen Shen

commit 334b0f4e9b1b4a1d475f803419d202f6c5e4d18e upstream. There is a race condition which results in a deadlock when rmdir and mkdir execute concurrently: $ ls /sys/fs/resctrl/c1/mon_groups/m1/ cpus cpus_list mon_data tasks Thread 1: rmdir /sys/fs/resctrl/c1 Thread 2: mkdir /sys/fs/resctrl/c1/mon_groups/m1 3 locks held by mkdir/48649: #0: (sb_writers#17){.+.+}, at: [<ffffffffb4ca2aa0>] mnt_want_write+0x20/0x50 #1: (&type->i_mutex_dir_key#8/1){+.+.}, at: [<ffffffffb4c8c13b>] filename_create+0x7b/0x170 #2: (rdtgroup_mutex){+.+.}, at: [<ffffffffb4a4389d>] rdtgroup_kn_lock_live+0x3d/0x70 4 locks held by rmdir/48652: #0: (sb_writers#17){.+.+}, at: [<ffffffffb4ca2aa0>] mnt_want_write+0x20/0x50 #1: (&type->i_mutex_dir_key#8/1){+.+.}, at: [<ffffffffb4c8c3cf>] do_rmdir+0x13f/0x1e0 #2: (&type->i_mutex_dir_key#8){++++}, at: [<ffffffffb4c86d5d>] vfs_rmdir+0x4d/0x120 #3: (rdtgroup_mutex){+.+.}, at: [<ffffffffb4a4389d>] rdtgroup_kn_lock_live+0x3d/0x70 Thread 1 is deleting control group "c1". Holding rdtgroup_mutex, kernfs_remove() removes all kernfs nodes under directory "c1" recursively, then waits for sub kernfs node "mon_groups" to drop active reference. Thread 2 is trying to create a subdirectory "m1" in the "mon_groups" directory. The wrapper kernfs_iop_mkdir() takes an active reference to the "mon_groups" directory but the code drops the active reference to the parent directory "c1" instead. As a result, Thread 1 is blocked on waiting for active reference to drop and never release rdtgroup_mutex, while Thread 2 is also blocked on trying to get rdtgroup_mutex. Thread 1 (rdtgroup_rmdir) Thread 2 (rdtgroup_mkdir) (rmdir /sys/fs/resctrl/c1) (mkdir /sys/fs/resctrl/c1/mon_groups/m1) ------------------------- ------------------------- kernfs_iop_mkdir /* * kn: "m1", parent_kn: "mon_groups", * prgrp_kn: parent_kn->parent: "c1", * * "mon_groups", parent_kn->active++: 1 */ kernfs_get_active(parent_kn) kernfs_iop_rmdir /* "c1", kn->active++ */ kernfs_get_active(kn) rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) /* "c1", kn->active-- */ kernfs_break_active_protection(kn) mutex_lock rdtgroup_rmdir_ctrl free_all_child_rdtgrp sentry->flags = RDT_DELETED rdtgroup_ctrl_remove rdtgrp->flags = RDT_DELETED kernfs_get(kn) kernfs_remove(rdtgrp->kn) __kernfs_remove /* "mon_groups", sub_kn */ atomic_add(KN_DEACTIVATED_BIAS, &sub_kn->active) kernfs_drain(sub_kn) /* * sub_kn->active == KN_DEACTIVATED_BIAS + 1, * waiting on sub_kn->active to drop, but it * never drops in Thread 2 which is blocked * on getting rdtgroup_mutex. */ Thread 1 hangs here ----> wait_event(sub_kn->active == KN_DEACTIVATED_BIAS) ... rdtgroup_mkdir rdtgroup_mkdir_mon(parent_kn, prgrp_kn) mkdir_rdt_prepare(parent_kn, prgrp_kn) rdtgroup_kn_lock_live(prgrp_kn) atomic_inc(&rdtgrp->waitcount) /* * "c1", prgrp_kn->active-- * * The active reference on "c1" is * dropped, but not matching the * actual active reference taken * on "mon_groups", thus causing * Thread 1 to wait forever while * holding rdtgroup_mutex. */ kernfs_break_active_protection( prgrp_kn) /* * Trying to get rdtgroup_mutex * which is held by Thread 1. */ Thread 2 hangs here ----> mutex_lock ... The problem is that the creation of a subdirectory in the "mon_groups" directory incorrectly releases the active protection of its parent directory instead of itself before it starts waiting for rdtgroup_mutex. This is triggered by the rdtgroup_mkdir() flow calling rdtgroup_kn_lock_live()/rdtgroup_kn_unlock() with kernfs node of the parent control group ("c1") as argument. It should be called with kernfs node "mon_groups" instead. What is currently missing is that the kn->priv of "mon_groups" is NULL instead of pointing to the rdtgrp. Fix it by pointing kn->priv to rdtgrp when "mon_groups" is created. Then it could be passed to rdtgroup_kn_lock_live()/rdtgroup_kn_unlock() instead. And then it operates on the same rdtgroup structure but handles the active reference of kernfs node "mon_groups" to prevent deadlock. The same changes are also made to the "mon_data" directories. This results in some unused function parameters that will be cleaned up in follow-up patch as the focus here is on the fix only in support of backporting efforts. Backporting notes: Since upstream commit fa7d949337cc ("x86/resctrl: Rename and move rdt files to a separate directory"), the file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c has been renamed and moved to arch/x86/kernel/cpu/resctrl/rdtgroup.c. Apply the change against file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c for older stable trees. Fixes: c7d9aac61311 ("x86/intel_rdt/cqm: Add mkdir support for RDT monitoring") Suggested-by: Reinette Chatre <reinette.chatre(a)intel.com> Signed-off-by: Xiaochen Shen <xiaochen.shen(a)intel.com> Signed-off-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> Reviewed-by: Tony Luck <tony.luck(a)intel.com> Acked-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Link: https://lkml.kernel.org/r/1578500886-21771-4-git-send-email-xiaochen.shen@i… --- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 77770ca..11c5acc 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -2005,7 +2005,7 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type, if (rdt_mon_capable) { ret = mongroup_create_dir(rdtgroup_default.kn, - NULL, "mon_groups", + &rdtgroup_default, "mon_groups", &kn_mongrp); if (ret) { dentry = ERR_PTR(ret); @@ -2415,7 +2415,7 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn, /* * Create the mon_data directory first. */ - ret = mongroup_create_dir(parent_kn, NULL, "mon_data", &kn); + ret = mongroup_create_dir(parent_kn, prgrp, "mon_data", &kn); if (ret) return ret; @@ -2568,7 +2568,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn, uint files = 0; int ret; - prdtgrp = rdtgroup_kn_lock_live(prgrp_kn); + prdtgrp = rdtgroup_kn_lock_live(parent_kn); rdt_last_cmd_clear(); if (!prdtgrp) { ret = -ENODEV; @@ -2643,7 +2643,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn, kernfs_activate(kn); /* - * The caller unlocks the prgrp_kn upon success. + * The caller unlocks the parent_kn upon success. */ return 0; @@ -2654,7 +2654,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn, out_free_rgrp: kfree(rdtgrp); out_unlock: - rdtgroup_kn_unlock(prgrp_kn); + rdtgroup_kn_unlock(parent_kn); return ret; } @@ -2692,7 +2692,7 @@ static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn, */ list_add_tail(&rdtgrp->mon.crdtgrp_list, &prgrp->mon.crdtgrp_list); - rdtgroup_kn_unlock(prgrp_kn); + rdtgroup_kn_unlock(parent_kn); return ret; } @@ -2735,7 +2735,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn, * Create an empty mon_groups directory to hold the subset * of tasks and cpus to monitor. */ - ret = mongroup_create_dir(kn, NULL, "mon_groups", NULL); + ret = mongroup_create_dir(kn, rdtgrp, "mon_groups", NULL); if (ret) { rdt_last_cmd_puts("kernfs subdir error\n"); goto out_del_list; @@ -2751,7 +2751,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn, out_common_fail: mkdir_rdt_prepare_clean(rdtgrp); out_unlock: - rdtgroup_kn_unlock(prgrp_kn); + rdtgroup_kn_unlock(parent_kn); return ret; } -- 1.8.3.1

5 years, 9 months

1
0
0 0

[PATCH 4.19 2/3] x86/resctrl: Fix use-after-free due to inaccurate refcount of rdtgroup

by Xiaochen Shen

commit 074fadee59ee7a9d2b216e9854bd4efb5dad679f upstream. There is a race condition in the following scenario which results in an use-after-free issue when reading a monitoring file and deleting the parent ctrl_mon group concurrently: Thread 1 calls atomic_inc() to take refcount of rdtgrp and then calls kernfs_break_active_protection() to drop the active reference of kernfs node in rdtgroup_kn_lock_live(). In Thread 2, kernfs_remove() is a blocking routine. It waits on all sub kernfs nodes to drop the active reference when removing all subtree kernfs nodes recursively. Thread 2 could block on kernfs_remove() until Thread 1 calls kernfs_break_active_protection(). Only after kernfs_remove() completes the refcount of rdtgrp could be trusted. Before Thread 1 calls atomic_inc() and kernfs_break_active_protection(), Thread 2 could call kfree() when the refcount of rdtgrp (sentry) is 0 instead of 1 due to the race. In Thread 1, in rdtgroup_kn_unlock(), referring to earlier rdtgrp memory (rdtgrp->waitcount) which was already freed in Thread 2 results in use-after-free issue. Thread 1 (rdtgroup_mondata_show) Thread 2 (rdtgroup_rmdir) -------------------------------- ------------------------- rdtgroup_kn_lock_live /* * kn active protection until * kernfs_break_active_protection(kn) */ rdtgrp = kernfs_to_rdtgroup(kn) rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) mutex_lock rdtgroup_rmdir_ctrl free_all_child_rdtgrp /* * sentry->waitcount should be 1 * but is 0 now due to the race. */ kfree(sentry)*[1] /* * Only after kernfs_remove() * completes, the refcount of * rdtgrp could be trusted. */ atomic_inc(&rdtgrp->waitcount) /* kn->active-- */ kernfs_break_active_protection(kn) rdtgroup_ctrl_remove rdtgrp->flags = RDT_DELETED /* * Blocking routine, wait for * all sub kernfs nodes to drop * active reference in * kernfs_break_active_protection. */ kernfs_remove(rdtgrp->kn) rdtgroup_kn_unlock mutex_unlock atomic_dec_and_test( &rdtgrp->waitcount) && (flags & RDT_DELETED) kernfs_unbreak_active_protection(kn) kfree(rdtgrp) mutex_lock mon_event_read rdtgroup_kn_unlock mutex_unlock /* * Use-after-free: refer to earlier rdtgrp * memory which was freed in [1]. */ atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) /* kn->active++ */ kernfs_unbreak_active_protection(kn) kfree(rdtgrp) Fix it by moving free_all_child_rdtgrp() to after kernfs_remove() in rdtgroup_rmdir_ctrl() to ensure it has the accurate refcount of rdtgrp. Backporting notes: Since upstream commit fa7d949337cc ("x86/resctrl: Rename and move rdt files to a separate directory"), the file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c has been renamed and moved to arch/x86/kernel/cpu/resctrl/rdtgroup.c. Apply the change against file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c for older stable trees. Fixes: f3cbeacaa06e ("x86/intel_rdt/cqm: Add rmdir support") Suggested-by: Reinette Chatre <reinette.chatre(a)intel.com> Signed-off-by: Xiaochen Shen <xiaochen.shen(a)intel.com> Signed-off-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> Reviewed-by: Tony Luck <tony.luck(a)intel.com> Acked-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Link: https://lkml.kernel.org/r/1578500886-21771-3-git-send-email-xiaochen.shen@i… --- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index db22ba0..77770ca 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -2877,13 +2877,13 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp, closid_free(rdtgrp->closid); free_rmid(rdtgrp->mon.rmid); + rdtgroup_ctrl_remove(kn, rdtgrp); + /* * Free all the child monitor group rmids. */ free_all_child_rdtgrp(rdtgrp); - rdtgroup_ctrl_remove(kn, rdtgrp); - return 0; } -- 1.8.3.1

5 years, 9 months

1
0
0 0

[PATCH 4.14 3/3] x86/resctrl: Fix a deadlock due to inaccurate reference

by Xiaochen Shen

commit 334b0f4e9b1b4a1d475f803419d202f6c5e4d18e upstream. There is a race condition which results in a deadlock when rmdir and mkdir execute concurrently: $ ls /sys/fs/resctrl/c1/mon_groups/m1/ cpus cpus_list mon_data tasks Thread 1: rmdir /sys/fs/resctrl/c1 Thread 2: mkdir /sys/fs/resctrl/c1/mon_groups/m1 3 locks held by mkdir/48649: #0: (sb_writers#17){.+.+}, at: [<ffffffffb4ca2aa0>] mnt_want_write+0x20/0x50 #1: (&type->i_mutex_dir_key#8/1){+.+.}, at: [<ffffffffb4c8c13b>] filename_create+0x7b/0x170 #2: (rdtgroup_mutex){+.+.}, at: [<ffffffffb4a4389d>] rdtgroup_kn_lock_live+0x3d/0x70 4 locks held by rmdir/48652: #0: (sb_writers#17){.+.+}, at: [<ffffffffb4ca2aa0>] mnt_want_write+0x20/0x50 #1: (&type->i_mutex_dir_key#8/1){+.+.}, at: [<ffffffffb4c8c3cf>] do_rmdir+0x13f/0x1e0 #2: (&type->i_mutex_dir_key#8){++++}, at: [<ffffffffb4c86d5d>] vfs_rmdir+0x4d/0x120 #3: (rdtgroup_mutex){+.+.}, at: [<ffffffffb4a4389d>] rdtgroup_kn_lock_live+0x3d/0x70 Thread 1 is deleting control group "c1". Holding rdtgroup_mutex, kernfs_remove() removes all kernfs nodes under directory "c1" recursively, then waits for sub kernfs node "mon_groups" to drop active reference. Thread 2 is trying to create a subdirectory "m1" in the "mon_groups" directory. The wrapper kernfs_iop_mkdir() takes an active reference to the "mon_groups" directory but the code drops the active reference to the parent directory "c1" instead. As a result, Thread 1 is blocked on waiting for active reference to drop and never release rdtgroup_mutex, while Thread 2 is also blocked on trying to get rdtgroup_mutex. Thread 1 (rdtgroup_rmdir) Thread 2 (rdtgroup_mkdir) (rmdir /sys/fs/resctrl/c1) (mkdir /sys/fs/resctrl/c1/mon_groups/m1) ------------------------- ------------------------- kernfs_iop_mkdir /* * kn: "m1", parent_kn: "mon_groups", * prgrp_kn: parent_kn->parent: "c1", * * "mon_groups", parent_kn->active++: 1 */ kernfs_get_active(parent_kn) kernfs_iop_rmdir /* "c1", kn->active++ */ kernfs_get_active(kn) rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) /* "c1", kn->active-- */ kernfs_break_active_protection(kn) mutex_lock rdtgroup_rmdir_ctrl free_all_child_rdtgrp sentry->flags = RDT_DELETED rdtgroup_ctrl_remove rdtgrp->flags = RDT_DELETED kernfs_get(kn) kernfs_remove(rdtgrp->kn) __kernfs_remove /* "mon_groups", sub_kn */ atomic_add(KN_DEACTIVATED_BIAS, &sub_kn->active) kernfs_drain(sub_kn) /* * sub_kn->active == KN_DEACTIVATED_BIAS + 1, * waiting on sub_kn->active to drop, but it * never drops in Thread 2 which is blocked * on getting rdtgroup_mutex. */ Thread 1 hangs here ----> wait_event(sub_kn->active == KN_DEACTIVATED_BIAS) ... rdtgroup_mkdir rdtgroup_mkdir_mon(parent_kn, prgrp_kn) mkdir_rdt_prepare(parent_kn, prgrp_kn) rdtgroup_kn_lock_live(prgrp_kn) atomic_inc(&rdtgrp->waitcount) /* * "c1", prgrp_kn->active-- * * The active reference on "c1" is * dropped, but not matching the * actual active reference taken * on "mon_groups", thus causing * Thread 1 to wait forever while * holding rdtgroup_mutex. */ kernfs_break_active_protection( prgrp_kn) /* * Trying to get rdtgroup_mutex * which is held by Thread 1. */ Thread 2 hangs here ----> mutex_lock ... The problem is that the creation of a subdirectory in the "mon_groups" directory incorrectly releases the active protection of its parent directory instead of itself before it starts waiting for rdtgroup_mutex. This is triggered by the rdtgroup_mkdir() flow calling rdtgroup_kn_lock_live()/rdtgroup_kn_unlock() with kernfs node of the parent control group ("c1") as argument. It should be called with kernfs node "mon_groups" instead. What is currently missing is that the kn->priv of "mon_groups" is NULL instead of pointing to the rdtgrp. Fix it by pointing kn->priv to rdtgrp when "mon_groups" is created. Then it could be passed to rdtgroup_kn_lock_live()/rdtgroup_kn_unlock() instead. And then it operates on the same rdtgroup structure but handles the active reference of kernfs node "mon_groups" to prevent deadlock. The same changes are also made to the "mon_data" directories. This results in some unused function parameters that will be cleaned up in follow-up patch as the focus here is on the fix only in support of backporting efforts. Backporting notes: Since upstream commit fa7d949337cc ("x86/resctrl: Rename and move rdt files to a separate directory"), the file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c has been renamed and moved to arch/x86/kernel/cpu/resctrl/rdtgroup.c. Apply the change against file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c for older stable trees. Fixes: c7d9aac61311 ("x86/intel_rdt/cqm: Add mkdir support for RDT monitoring") Suggested-by: Reinette Chatre <reinette.chatre(a)intel.com> Signed-off-by: Xiaochen Shen <xiaochen.shen(a)intel.com> Signed-off-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> Reviewed-by: Tony Luck <tony.luck(a)intel.com> Acked-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Link: https://lkml.kernel.org/r/1578500886-21771-4-git-send-email-xiaochen.shen@i… --- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 0157496..0ec30b2 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -1107,7 +1107,7 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type, if (rdt_mon_capable) { ret = mongroup_create_dir(rdtgroup_default.kn, - NULL, "mon_groups", + &rdtgroup_default, "mon_groups", &kn_mongrp); if (ret) { dentry = ERR_PTR(ret); @@ -1499,7 +1499,7 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn, /* * Create the mon_data directory first. */ - ret = mongroup_create_dir(parent_kn, NULL, "mon_data", &kn); + ret = mongroup_create_dir(parent_kn, prgrp, "mon_data", &kn); if (ret) return ret; @@ -1533,7 +1533,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn, uint files = 0; int ret; - prdtgrp = rdtgroup_kn_lock_live(prgrp_kn); + prdtgrp = rdtgroup_kn_lock_live(parent_kn); if (!prdtgrp) { ret = -ENODEV; goto out_unlock; @@ -1589,7 +1589,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn, kernfs_activate(kn); /* - * The caller unlocks the prgrp_kn upon success. + * The caller unlocks the parent_kn upon success. */ return 0; @@ -1600,7 +1600,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn, out_free_rgrp: kfree(rdtgrp); out_unlock: - rdtgroup_kn_unlock(prgrp_kn); + rdtgroup_kn_unlock(parent_kn); return ret; } @@ -1638,7 +1638,7 @@ static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn, */ list_add_tail(&rdtgrp->mon.crdtgrp_list, &prgrp->mon.crdtgrp_list); - rdtgroup_kn_unlock(prgrp_kn); + rdtgroup_kn_unlock(parent_kn); return ret; } @@ -1675,7 +1675,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn, * Create an empty mon_groups directory to hold the subset * of tasks and cpus to monitor. */ - ret = mongroup_create_dir(kn, NULL, "mon_groups", NULL); + ret = mongroup_create_dir(kn, rdtgrp, "mon_groups", NULL); if (ret) goto out_id_free; } @@ -1688,7 +1688,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn, out_common_fail: mkdir_rdt_prepare_clean(rdtgrp); out_unlock: - rdtgroup_kn_unlock(prgrp_kn); + rdtgroup_kn_unlock(parent_kn); return ret; } -- 1.8.3.1

5 years, 9 months

1
0
0 0

[PATCH 4.14 2/3] x86/resctrl: Fix use-after-free due to inaccurate refcount of rdtgroup

by Xiaochen Shen

commit 074fadee59ee7a9d2b216e9854bd4efb5dad679f upstream. There is a race condition in the following scenario which results in an use-after-free issue when reading a monitoring file and deleting the parent ctrl_mon group concurrently: Thread 1 calls atomic_inc() to take refcount of rdtgrp and then calls kernfs_break_active_protection() to drop the active reference of kernfs node in rdtgroup_kn_lock_live(). In Thread 2, kernfs_remove() is a blocking routine. It waits on all sub kernfs nodes to drop the active reference when removing all subtree kernfs nodes recursively. Thread 2 could block on kernfs_remove() until Thread 1 calls kernfs_break_active_protection(). Only after kernfs_remove() completes the refcount of rdtgrp could be trusted. Before Thread 1 calls atomic_inc() and kernfs_break_active_protection(), Thread 2 could call kfree() when the refcount of rdtgrp (sentry) is 0 instead of 1 due to the race. In Thread 1, in rdtgroup_kn_unlock(), referring to earlier rdtgrp memory (rdtgrp->waitcount) which was already freed in Thread 2 results in use-after-free issue. Thread 1 (rdtgroup_mondata_show) Thread 2 (rdtgroup_rmdir) -------------------------------- ------------------------- rdtgroup_kn_lock_live /* * kn active protection until * kernfs_break_active_protection(kn) */ rdtgrp = kernfs_to_rdtgroup(kn) rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) mutex_lock rdtgroup_rmdir_ctrl free_all_child_rdtgrp /* * sentry->waitcount should be 1 * but is 0 now due to the race. */ kfree(sentry)*[1] /* * Only after kernfs_remove() * completes, the refcount of * rdtgrp could be trusted. */ atomic_inc(&rdtgrp->waitcount) /* kn->active-- */ kernfs_break_active_protection(kn) rdtgroup_ctrl_remove rdtgrp->flags = RDT_DELETED /* * Blocking routine, wait for * all sub kernfs nodes to drop * active reference in * kernfs_break_active_protection. */ kernfs_remove(rdtgrp->kn) rdtgroup_kn_unlock mutex_unlock atomic_dec_and_test( &rdtgrp->waitcount) && (flags & RDT_DELETED) kernfs_unbreak_active_protection(kn) kfree(rdtgrp) mutex_lock mon_event_read rdtgroup_kn_unlock mutex_unlock /* * Use-after-free: refer to earlier rdtgrp * memory which was freed in [1]. */ atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) /* kn->active++ */ kernfs_unbreak_active_protection(kn) kfree(rdtgrp) Fix it by moving free_all_child_rdtgrp() to after kernfs_remove() in rdtgroup_rmdir_ctrl() to ensure it has the accurate refcount of rdtgrp. Backporting notes: Since upstream commit fa7d949337cc ("x86/resctrl: Rename and move rdt files to a separate directory"), the file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c has been renamed and moved to arch/x86/kernel/cpu/resctrl/rdtgroup.c. Apply the change against file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c for older stable trees. Upstream commit 17eafd076291 ("x86/intel_rdt: Split resource group removal in two") moved part of resource group removal code from rdtgroup_rmdir_mon() into a separate function rdtgroup_ctrl_remove(). Apply the change against original code base of rdtgroup_rmdir_mon() for older stable trees. Fixes: f3cbeacaa06e ("x86/intel_rdt/cqm: Add rmdir support") Suggested-by: Reinette Chatre <reinette.chatre(a)intel.com> Signed-off-by: Xiaochen Shen <xiaochen.shen(a)intel.com> Signed-off-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> Reviewed-by: Tony Luck <tony.luck(a)intel.com> Acked-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Link: https://lkml.kernel.org/r/1578500886-21771-3-git-send-email-xiaochen.shen@i… --- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 7349969..0157496 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -1800,11 +1800,6 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp, closid_free(rdtgrp->closid); free_rmid(rdtgrp->mon.rmid); - /* - * Free all the child monitor group rmids. - */ - free_all_child_rdtgrp(rdtgrp); - list_del(&rdtgrp->rdtgroup_list); /* @@ -1814,6 +1809,11 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp, kernfs_get(kn); kernfs_remove(rdtgrp->kn); + /* + * Free all the child monitor group rmids. + */ + free_all_child_rdtgrp(rdtgrp); + return 0; } -- 1.8.3.1

5 years, 9 months

1
0
0 0

[PATCH 4.14 1/3] x86/resctrl: Fix use-after-free when deleting resource groups

by Xiaochen Shen

commit b8511ccc75c033f6d54188ea4df7bf1e85778740 upstream. A resource group (rdtgrp) contains a reference count (rdtgrp->waitcount) that indicates how many waiters expect this rdtgrp to exist. Waiters could be waiting on rdtgroup_mutex or some work sitting on a task's workqueue for when the task returns from kernel mode or exits. The deletion of a rdtgrp is intended to have two phases: (1) while holding rdtgroup_mutex the necessary cleanup is done and rdtgrp->flags is set to RDT_DELETED, (2) after releasing the rdtgroup_mutex, the rdtgrp structure is freed only if there are no waiters and its flag is set to RDT_DELETED. Upon gaining access to rdtgroup_mutex or rdtgrp, a waiter is required to check for the RDT_DELETED flag. When unmounting the resctrl file system or deleting ctrl_mon groups, all of the subdirectories are removed and the data structure of rdtgrp is forcibly freed without checking rdtgrp->waitcount. If at this point there was a waiter on rdtgrp then a use-after-free issue occurs when the waiter starts running and accesses the rdtgrp structure it was waiting on. See kfree() calls in [1], [2] and [3] in these two call paths in following scenarios: (1) rdt_kill_sb() -> rmdir_all_sub() -> free_all_child_rdtgrp() (2) rdtgroup_rmdir() -> rdtgroup_rmdir_ctrl() -> free_all_child_rdtgrp() There are several scenarios that result in use-after-free issue in following: Scenario 1: ----------- In Thread 1, rdtgroup_tasks_write() adds a task_work callback move_myself(). If move_myself() is scheduled to execute after Thread 2 rdt_kill_sb() is finished, referring to earlier rdtgrp memory (rdtgrp->waitcount) which was already freed in Thread 2 results in use-after-free issue. Thread 1 (rdtgroup_tasks_write) Thread 2 (rdt_kill_sb) ------------------------------- ---------------------- rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) mutex_lock rdtgroup_move_task __rdtgroup_move_task /* * Take an extra refcount, so rdtgrp cannot be freed * before the call back move_myself has been invoked */ atomic_inc(&rdtgrp->waitcount) /* Callback move_myself will be scheduled for later */ task_work_add(move_myself) rdtgroup_kn_unlock mutex_unlock atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) mutex_lock rmdir_all_sub /* * sentry and rdtgrp are freed * without checking refcount */ free_all_child_rdtgrp kfree(sentry)*[1] kfree(rdtgrp)*[2] mutex_unlock /* * Callback is scheduled to execute * after rdt_kill_sb is finished */ move_myself /* * Use-after-free: refer to earlier rdtgrp * memory which was freed in [1] or [2]. */ atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) kfree(rdtgrp) Scenario 2: ----------- In Thread 1, rdtgroup_tasks_write() adds a task_work callback move_myself(). If move_myself() is scheduled to execute after Thread 2 rdtgroup_rmdir() is finished, referring to earlier rdtgrp memory (rdtgrp->waitcount) which was already freed in Thread 2 results in use-after-free issue. Thread 1 (rdtgroup_tasks_write) Thread 2 (rdtgroup_rmdir) ------------------------------- ------------------------- rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) mutex_lock rdtgroup_move_task __rdtgroup_move_task /* * Take an extra refcount, so rdtgrp cannot be freed * before the call back move_myself has been invoked */ atomic_inc(&rdtgrp->waitcount) /* Callback move_myself will be scheduled for later */ task_work_add(move_myself) rdtgroup_kn_unlock mutex_unlock atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) rdtgroup_kn_lock_live atomic_inc(&rdtgrp->waitcount) mutex_lock rdtgroup_rmdir_ctrl free_all_child_rdtgrp /* * sentry is freed without * checking refcount */ kfree(sentry)*[3] rdtgroup_ctrl_remove rdtgrp->flags = RDT_DELETED rdtgroup_kn_unlock mutex_unlock atomic_dec_and_test( &rdtgrp->waitcount) && (flags & RDT_DELETED) kfree(rdtgrp) /* * Callback is scheduled to execute * after rdt_kill_sb is finished */ move_myself /* * Use-after-free: refer to earlier rdtgrp * memory which was freed in [3]. */ atomic_dec_and_test(&rdtgrp->waitcount) && (flags & RDT_DELETED) kfree(rdtgrp) If CONFIG_DEBUG_SLAB=y, Slab corruption on kmalloc-2k can be observed like following. Note that "0x6b" is POISON_FREE after kfree(). The corrupted bits "0x6a", "0x64" at offset 0x424 correspond to waitcount member of struct rdtgroup which was freed: Slab corruption (Not tainted): kmalloc-2k start=ffff9504c5b0d000, len=2048 420: 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkjkkkkkkkkkkk Single bit error detected. Probably bad RAM. Run memtest86+ or a similar memory test tool. Next obj: start=ffff9504c5b0d800, len=2048 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Slab corruption (Not tainted): kmalloc-2k start=ffff9504c58ab800, len=2048 420: 6b 6b 6b 6b 64 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkdkkkkkkkkkkk Prev obj: start=ffff9504c58ab000, len=2048 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Fix this by taking reference count (waitcount) of rdtgrp into account in the two call paths that currently do not do so. Instead of always freeing the resource group it will only be freed if there are no waiters on it. If there are waiters, the resource group will have its flags set to RDT_DELETED. It will be left to the waiter to free the resource group when it starts running and finding that it was the last waiter and the resource group has been removed (rdtgrp->flags & RDT_DELETED) since. (1) rdt_kill_sb() -> rmdir_all_sub() -> free_all_child_rdtgrp() (2) rdtgroup_rmdir() -> rdtgroup_rmdir_ctrl() -> free_all_child_rdtgrp() Backporting notes: Since upstream commit fa7d949337cc ("x86/resctrl: Rename and move rdt files to a separate directory"), the file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c has been renamed and moved to arch/x86/kernel/cpu/resctrl/rdtgroup.c. Apply the change against file arch/x86/kernel/cpu/intel_rdt_rdtgroup.c in older stable trees. Fixes: f3cbeacaa06e ("x86/intel_rdt/cqm: Add rmdir support") Fixes: 60cf5e101fd4 ("x86/intel_rdt: Add mkdir to resctrl file system") Suggested-by: Reinette Chatre <reinette.chatre(a)intel.com> Signed-off-by: Xiaochen Shen <xiaochen.shen(a)intel.com> Signed-off-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> Reviewed-by: Tony Luck <tony.luck(a)intel.com> Acked-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Link: https://lkml.kernel.org/r/1578500886-21771-2-git-send-email-xiaochen.shen@i… --- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 2dae1b3..7349969 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -1260,7 +1260,11 @@ static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp) list_for_each_entry_safe(sentry, stmp, head, mon.crdtgrp_list) { free_rmid(sentry->mon.rmid); list_del(&sentry->mon.crdtgrp_list); - kfree(sentry); + + if (atomic_read(&sentry->waitcount) != 0) + sentry->flags = RDT_DELETED; + else + kfree(sentry); } } @@ -1294,7 +1298,11 @@ static void rmdir_all_sub(void) kernfs_remove(rdtgrp->kn); list_del(&rdtgrp->rdtgroup_list); - kfree(rdtgrp); + + if (atomic_read(&rdtgrp->waitcount) != 0) + rdtgrp->flags = RDT_DELETED; + else + kfree(rdtgrp); } /* Notify online CPUs to update per cpu storage and PQR_ASSOC MSR */ update_closid_rmid(cpu_online_mask, &rdtgroup_default); -- 1.8.3.1

5 years, 9 months

1
0
0 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

Linux-stable-mirror