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2025-12-07fs/proc: fix uaf in proc_readdir_de()Wei Yang1-3/+9
commit 895b4c0c79b092d732544011c3cecaf7322c36a1 upstream. Pde is erased from subdir rbtree through rb_erase(), but not set the node to EMPTY, which may result in uaf access. We should use RB_CLEAR_NODE() set the erased node to EMPTY, then pde_subdir_next() will return NULL to avoid uaf access. We found an uaf issue while using stress-ng testing, need to run testcase getdent and tun in the same time. The steps of the issue is as follows: 1) use getdent to traverse dir /proc/pid/net/dev_snmp6/, and current pde is tun3; 2) in the [time windows] unregister netdevice tun3 and tun2, and erase them from rbtree. erase tun3 first, and then erase tun2. the pde(tun2) will be released to slab; 3) continue to getdent process, then pde_subdir_next() will return pde(tun2) which is released, it will case uaf access. CPU 0 | CPU 1 ------------------------------------------------------------------------- traverse dir /proc/pid/net/dev_snmp6/ | unregister_netdevice(tun->dev) //tun3 tun2 sys_getdents64() | iterate_dir() | proc_readdir() | proc_readdir_de() | snmp6_unregister_dev() pde_get(de); | proc_remove() read_unlock(&proc_subdir_lock); | remove_proc_subtree() | write_lock(&proc_subdir_lock); [time window] | rb_erase(&root->subdir_node, &parent->subdir); | write_unlock(&proc_subdir_lock); read_lock(&proc_subdir_lock); | next = pde_subdir_next(de); | pde_put(de); | de = next; //UAF | rbtree of dev_snmp6 | pde(tun3) / \ NULL pde(tun2) Link: https://lkml.kernel.org/r/20251025024233.158363-1-albin_yang@163.com Signed-off-by: Wei Yang <albinwyang@tencent.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: wangzijie <wangzijie1@honor.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-09-19proc: fix type confusion in pde_set_flags()wangzijie1-1/+2
[ Upstream commit 0ce9398aa0830f15f92bbed73853f9861c3e74ff ] Commit 2ce3d282bd50 ("proc: fix missing pde_set_flags() for net proc files") missed a key part in the definition of proc_dir_entry: union { const struct proc_ops *proc_ops; const struct file_operations *proc_dir_ops; }; So dereference of ->proc_ops assumes it is a proc_ops structure results in type confusion and make NULL check for 'proc_ops' not work for proc dir. Add !S_ISDIR(dp->mode) test before calling pde_set_flags() to fix it. Link: https://lkml.kernel.org/r/20250904135715.3972782-1-wangzijie1@honor.com Fixes: 2ce3d282bd50 ("proc: fix missing pde_set_flags() for net proc files") Signed-off-by: wangzijie <wangzijie1@honor.com> Reported-by: Brad Spengler <spender@grsecurity.net> Closes: https://lore.kernel.org/all/20250903065758.3678537-1-wangzijie1@honor.com/ Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Stefano Brivio <sbrivio@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-09-09proc: fix missing pde_set_flags() for net proc fileswangzijie1-17/+21
commit 2ce3d282bd5050fca8577defeff08ada0d55d062 upstream. To avoid potential UAF issues during module removal races, we use pde_set_flags() to save proc_ops flags in PDE itself before proc_register(), and then use pde_has_proc_*() helpers instead of directly dereferencing pde->proc_ops->*. However, the pde_set_flags() call was missing when creating net related proc files. This omission caused incorrect behavior which FMODE_LSEEK was being cleared inappropriately in proc_reg_open() for net proc files. Lars reported it in this link[1]. Fix this by ensuring pde_set_flags() is called when register proc entry, and add NULL check for proc_ops in pde_set_flags(). [wangzijie1@honor.com: stash pde->proc_ops in a local const variable, per Christian] Link: https://lkml.kernel.org/r/20250821105806.1453833-1-wangzijie1@honor.com Link: https://lkml.kernel.org/r/20250818123102.959595-1-wangzijie1@honor.com Link: https://lore.kernel.org/all/20250815195616.64497967@chagall.paradoxon.rec/ [1] Fixes: ff7ec8dc1b64 ("proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al") Signed-off-by: wangzijie <wangzijie1@honor.com> Reported-by: Lars Wendler <polynomial-c@gmx.de> Tested-by: Stefano Brivio <sbrivio@redhat.com> Tested-by: Petr Vaněk <pv@excello.cz> Tested by: Lars Wendler <polynomial-c@gmx.de> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Kirill A. Shutemov <k.shutemov@gmail.com> Cc: wangzijie <wangzijie1@honor.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-15proc: use the same treatment to check proc_lseek as ones for proc_read_iter ↵wangzijie3-1/+8
et.al [ Upstream commit ff7ec8dc1b646296f8d94c39339e8d3833d16c05 ] Check pde->proc_ops->proc_lseek directly may cause UAF in rmmod scenario. It's a gap in proc_reg_open() after commit 654b33ada4ab("proc: fix UAF in proc_get_inode()"). Followed by AI Viro's suggestion, fix it in same manner. Link: https://lkml.kernel.org/r/20250607021353.1127963-1-wangzijie1@honor.com Fixes: 3f61631d47f1 ("take care to handle NULL ->proc_lseek()") Signed-off-by: wangzijie <wangzijie1@honor.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com> Cc: Kirill A. Shuemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17fix proc_sys_compare() handling of in-lookup dentriesAl Viro2-8/+12
[ Upstream commit b969f9614885c20f903e1d1f9445611daf161d6d ] There's one case where ->d_compare() can be called for an in-lookup dentry; usually that's nothing special from ->d_compare() point of view, but... proc_sys_compare() is weird. The thing is, /proc/sys subdirectories can look differently for different processes. Up to and including having the same name resolve to different dentries - all of them hashed. The way it's done is ->d_compare() refusing to admit a match unless this dentry is supposed to be visible to this caller. The information needed to discriminate between them is stored in inode; it is set during proc_sys_lookup() and until it's done d_splice_alias() we really can't tell who should that dentry be visible for. Normally there's no negative dentries in /proc/sys; we can run into a dying dentry in RCU dcache lookup, but those can be safely rejected. However, ->d_compare() is also called for in-lookup dentries, before they get positive - or hashed, for that matter. In case of match we will wait until dentry leaves in-lookup state and repeat ->d_compare() afterwards. In other words, the right behaviour is to treat the name match as sufficient for in-lookup dentries; if dentry is not for us, we'll see that when we recheck once proc_sys_lookup() is done with it. While we are at it, fix the misspelled READ_ONCE and WRITE_ONCE there. Fixes: d9171b934526 ("parallel lookups machinery, part 4 (and last)") Reported-by: NeilBrown <neilb@brown.name> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: NeilBrown <neil@brown.name> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10fs/procfs: fix the comment above proc_pid_wchan()Bart Van Assche1-1/+1
[ Upstream commit 6287fbad1cd91f0c25cdc3a580499060828a8f30 ] proc_pid_wchan() used to report kernel addresses to user space but that is no longer the case today. Bring the comment above proc_pid_wchan() in sync with the implementation. Link: https://lkml.kernel.org/r/20250319210222.1518771-1-bvanassche@acm.org Fixes: b2f73922d119 ("fs/proc, core/debug: Don't expose absolute kernel addresses via wchan") Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: Kees Cook <kees@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-28proc: fix UAF in proc_get_inode()Ye Bin3-4/+26
commit 654b33ada4ab5e926cd9c570196fefa7bec7c1df upstream. Fix race between rmmod and /proc/XXX's inode instantiation. The bug is that pde->proc_ops don't belong to /proc, it belongs to a module, therefore dereferencing it after /proc entry has been registered is a bug unless use_pde/unuse_pde() pair has been used. use_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops never changes so information necessary for inode instantiation can be saved _before_ proc_register() in PDE itself and used later, avoiding pde->proc_ops->... dereference. rmmod lookup sys_delete_module proc_lookup_de pde_get(de); proc_get_inode(dir->i_sb, de); mod->exit() proc_remove remove_proc_subtree proc_entry_rundown(de); free_module(mod); if (S_ISREG(inode->i_mode)) if (de->proc_ops->proc_read_iter) --> As module is already freed, will trigger UAF BUG: unable to handle page fault for address: fffffbfff80a702b PGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:proc_get_inode+0x302/0x6e0 RSP: 0018:ffff88811c837998 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007 RDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158 RBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20 R10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78f0 R13: ffff888100518048 R14: ffff8881299a6004 R15: 0000000000000001 FS: 00007f95b9686840(0000) GS:ffff8883af100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffbfff80a702b CR3: 0000000117dd2000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> proc_lookup_de+0x11f/0x2e0 __lookup_slow+0x188/0x350 walk_component+0x2ab/0x4f0 path_lookupat+0x120/0x660 filename_lookup+0x1ce/0x560 vfs_statx+0xac/0x150 __do_sys_newstat+0x96/0x110 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e [adobriyan@gmail.com: don't do 2 atomic ops on the common path] Link: https://lkml.kernel.org/r/3d25ded0-1739-447e-812b-e34da7990dcf@p183 Fixes: 778f3dd5a13c ("Fix procfs compat_ioctl regression") Signed-off-by: Ye Bin <yebin10@huawei.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: David S. Miller <davem@davemloft.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28hrtimer: Use and report correct timerslack values for realtime tasksFelix Moessbauer1-4/+5
commit ed4fb6d7ef68111bb539283561953e5c6e9a6e38 upstream. The timerslack_ns setting is used to specify how much the hardware timers should be delayed, to potentially dispatch multiple timers in a single interrupt. This is a performance optimization. Timers of realtime tasks (having a realtime scheduling policy) should not be delayed. This logic was inconsitently applied to the hrtimers, leading to delays of realtime tasks which used timed waits for events (e.g. condition variables). Due to the downstream override of the slack for rt tasks, the procfs reported incorrect (non-zero) timerslack_ns values. This is changed by setting the timer_slack_ns task attribute to 0 for all tasks with a rt policy. By that, downstream users do not need to specially handle rt tasks (w.r.t. the slack), and the procfs entry shows the correct value of "0". Setting non-zero slack values (either via procfs or PR_SET_TIMERSLACK) on tasks with a rt policy is ignored, as stated in "man 2 PR_SET_TIMERSLACK": Timer slack is not applied to threads that are scheduled under a real-time scheduling policy (see sched_setscheduler(2)). The special handling of timerslack on rt tasks in downstream users is removed as well. Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20240814121032.368444-2-felix.moessbauer@siemens.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-21fs/proc: do_task_stat: Fix ESP not readable during coredumpNam Cao1-1/+1
commit ab251dacfbae28772c897f068a4184f478189ff2 upstream. The field "eip" (instruction pointer) and "esp" (stack pointer) of a task can be read from /proc/PID/stat. These fields can be interesting for coredump. However, these fields were disabled by commit 0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in /proc/PID/stat"), because it is generally unsafe to do so. But it is safe for a coredumping process, and therefore exceptions were made: - for a coredumping thread by commit fd7d56270b52 ("fs/proc: Report eip/esp in /prod/PID/stat for coredumping"). - for all other threads in a coredumping process by commit cb8f381f1613 ("fs/proc/array.c: allow reporting eip/esp for all coredumping threads"). The above two commits check the PF_DUMPCORE flag to determine a coredump thread and the PF_EXITING flag for the other threads. Unfortunately, commit 92307383082d ("coredump: Don't perform any cleanups before dumping core") moved coredump to happen earlier and before PF_EXITING is set. Thus, checking PF_EXITING is no longer the correct way to determine threads in a coredumping process. Instead of PF_EXITING, use PF_POSTCOREDUMP to determine the other threads. Checking of PF_EXITING was added for coredumping, so it probably can now be removed. But it doesn't hurt to keep. Fixes: 92307383082d ("coredump: Don't perform any cleanups before dumping core") Cc: stable@vger.kernel.org Cc: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kees Cook <kees@kernel.org> Signed-off-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/d89af63d478d6c64cc46a01420b46fd6eb147d6f.1735805772.git.namcao@linutronix.de Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-23fs/proc: fix softlockup in __read_vmcore (part 2)Rik van Riel1-0/+2
commit cbc5dde0a461240046e8a41c43d7c3b76d5db952 upstream. Since commit 5cbcb62dddf5 ("fs/proc: fix softlockup in __read_vmcore") the number of softlockups in __read_vmcore at kdump time have gone down, but they still happen sometimes. In a memory constrained environment like the kdump image, a softlockup is not just a harmless message, but it can interfere with things like RCU freeing memory, causing the crashdump to get stuck. The second loop in __read_vmcore has a lot more opportunities for natural sleep points, like scheduling out while waiting for a data write to happen, but apparently that is not always enough. Add a cond_resched() to the second loop in __read_vmcore to (hopefully) get rid of the softlockups. Link: https://lkml.kernel.org/r/20250110102821.2a37581b@fangorn Fixes: 5cbcb62dddf5 ("fs/proc: fix softlockup in __read_vmcore") Signed-off-by: Rik van Riel <riel@surriel.com> Reported-by: Breno Leitao <leitao@debian.org> Cc: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14fs/proc/kcore.c: Clear ret value in read_kcore_iter after successful ↵Jiri Olsa1-0/+1
iov_iter_zero commit 088f294609d8f8816dc316681aef2eb61982e0da upstream. If iov_iter_zero succeeds after failed copy_from_kernel_nofault, we need to reset the ret value to zero otherwise it will be returned as final return value of read_kcore_iter. This fixes objdump -d dump over /proc/kcore for me. Cc: stable@vger.kernel.org Cc: Alexander Gordeev <agordeev@linux.ibm.com> Fixes: 3d5854d75e31 ("fs/proc/kcore.c: allow translation of physical memory addresses") Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20241121231118.3212000-1-jolsa@kernel.org Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14fs/proc/kcore.c: fix coccinelle reported ERROR instancesMirsad Todorovac1-5/+5
[ Upstream commit 82e33f249f1126cf3c5f39a31b850d485ac33bc3 ] Coccinelle complains about the nested reuse of the pointer `iter' with different pointer type: ./fs/proc/kcore.c:515:26-30: ERROR: invalid reference to the index variable of the iterator on line 499 ./fs/proc/kcore.c:534:23-27: ERROR: invalid reference to the index variable of the iterator on line 499 ./fs/proc/kcore.c:550:40-44: ERROR: invalid reference to the index variable of the iterator on line 499 ./fs/proc/kcore.c:568:27-31: ERROR: invalid reference to the index variable of the iterator on line 499 ./fs/proc/kcore.c:581:28-32: ERROR: invalid reference to the index variable of the iterator on line 499 ./fs/proc/kcore.c:599:27-31: ERROR: invalid reference to the index variable of the iterator on line 499 ./fs/proc/kcore.c:607:38-42: ERROR: invalid reference to the index variable of the iterator on line 499 ./fs/proc/kcore.c:614:26-30: ERROR: invalid reference to the index variable of the iterator on line 499 Replacing `struct kcore_list *iter' with `struct kcore_list *tmp' doesn't change the scope and the functionality is the same and coccinelle seems happy. NOTE: There was an issue with using `struct kcore_list *pos' as the nested iterator. The build did not work! [akpm@linux-foundation.org: s/tmp/pos/] Link: https://lkml.kernel.org/r/20241029054651.86356-2-mtodorovac69@gmail.com Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1] Link: https://lkml.kernel.org/r/20220331223700.902556-1-jakobkoschel@gmail.com Fixes: 04d168c6d42d ("fs/proc/kcore.c: remove check of list iterator against head past the loop body") Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com> Signed-off-by: Mirsad Todorovac <mtodorovac69@gmail.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Brian Johannesmeyer" <bjohannesmeyer@gmail.com> Cc: Cristiano Giuffrida <c.giuffrida@vu.nl> Cc: "Bos, H.J." <h.j.bos@vu.nl> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Yang Li <yang.lee@linux.alibaba.com> Cc: Baoquan He <bhe@redhat.com> Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: Yan Zhen <yanzhen@vivo.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14proc/softirqs: replace seq_printf with seq_put_decimal_ull_widthDavid Wang1-1/+1
[ Upstream commit 84b9749a3a704dcc824a88aa8267247c801d51e4 ] seq_printf is costy, on a system with n CPUs, reading /proc/softirqs would yield 10*n decimal values, and the extra cost parsing format string grows linearly with number of cpus. Replace seq_printf with seq_put_decimal_ull_width have significant performance improvement. On an 8CPUs system, reading /proc/softirqs show ~40% performance gain with this patch. Signed-off-by: David Wang <00107082@163.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-14fs/proc: fix compile warning about variable 'vmcore_mmap_ops'Qi Xi1-4/+5
commit b8ee299855f08539e04d6c1a6acb3dc9e5423c00 upstream. When build with !CONFIG_MMU, the variable 'vmcore_mmap_ops' is defined but not used: >> fs/proc/vmcore.c:458:42: warning: unused variable 'vmcore_mmap_ops' 458 | static const struct vm_operations_struct vmcore_mmap_ops = { Fix this by only defining it when CONFIG_MMU is enabled. Link: https://lkml.kernel.org/r/20241101034803.9298-1-xiqi2@huawei.com Fixes: 9cb218131de1 ("vmcore: introduce remap_oldmem_pfn_range()") Signed-off-by: Qi Xi <xiqi2@huawei.com> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/lkml/202410301936.GcE8yUos-lkp@intel.com/ Cc: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Wang ShaoBo <bobo.shaobowang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-08fs/proc/kcore.c: allow translation of physical memory addressesAlexander Gordeev1-2/+34
[ Upstream commit 3d5854d75e3187147613130561b58f0b06166172 ] When /proc/kcore is read an attempt to read the first two pages results in HW-specific page swap on s390 and another (so called prefix) pages are accessed instead. That leads to a wrong read. Allow architecture-specific translation of memory addresses using kc_xlate_dev_mem_ptr() and kc_unxlate_dev_mem_ptr() callbacks similarily to /dev/mem xlate_dev_mem_ptr() and unxlate_dev_mem_ptr() callbacks. That way an architecture can deal with specific physical memory ranges. Re-use the existing /dev/mem callback implementation on s390, which handles the described prefix pages swapping correctly. For other architectures the default callback is basically NOP. It is expected the condition (vaddr == __va(__pa(vaddr))) always holds true for KCORE_RAM memory type. Link: https://lkml.kernel.org/r/20240930122119.1651546-1-agordeev@linux.ibm.com Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Suggested-by: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-08fs/proc/kcore: reinstate bounce buffer for KCORE_TEXT regionsLorenzo Stoakes1-3/+14
[ Upstream commit 17457784004c84178798432a029ab20e14f728b1 ] Some architectures do not populate the entire range categorised by KCORE_TEXT, so we must ensure that the kernel address we read from is valid. Unfortunately there is no solution currently available to do so with a purely iterator solution so reinstate the bounce buffer in this instance so we can use copy_from_kernel_nofault() in order to avoid page faults when regions are unmapped. This change partly reverts commit 2e1c0170771e ("fs/proc/kcore: avoid bounce buffer for ktext data"), reinstating the bounce buffer, but adapts the code to continue to use an iterator. [lstoakes@gmail.com: correct comment to be strictly correct about reasoning] Link: https://lkml.kernel.org/r/525a3f14-74fa-4c22-9fca-9dab4de8a0c3@lucifer.local Link: https://lkml.kernel.org/r/20230731215021.70911-1-lstoakes@gmail.com Fixes: 2e1c0170771e ("fs/proc/kcore: avoid bounce buffer for ktext data") Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reported-by: Jiri Olsa <olsajiri@gmail.com> Closes: https://lore.kernel.org/all/ZHc2fm+9daF6cgCE@krava Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Will Deacon <will@kernel.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liu Shixin <liushixin2@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thorsten Leemhuis <regressions@leemhuis.info> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: 3d5854d75e31 ("fs/proc/kcore.c: allow translation of physical memory addresses") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-08fs/proc/kcore: convert read_kcore() to read_kcore_iter()Lorenzo Stoakes1-18/+18
[ Upstream commit 46c0d6d0904a10785faabee53fe53ee1aa718fea ] For the time being we still use a bounce buffer for vread(), however in the next patch we will convert this to interact directly with the iterator and eliminate the bounce buffer altogether. Link: https://lkml.kernel.org/r/ebe12c8d70eebd71f487d80095605f3ad0d1489c.1679511146.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Liu Shixin <liushixin2@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: 3d5854d75e31 ("fs/proc/kcore.c: allow translation of physical memory addresses") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-08fs/proc/kcore: avoid bounce buffer for ktext dataLorenzo Stoakes1-12/+5
[ Upstream commit 2e1c0170771e6bf31bc785ea43a44e6e85e36268 ] Patch series "convert read_kcore(), vread() to use iterators", v8. While reviewing Baoquan's recent changes to permit vread() access to vm_map_ram regions of vmalloc allocations, Willy pointed out [1] that it would be nice to refactor vread() as a whole, since its only user is read_kcore() and the existing form of vread() necessitates the use of a bounce buffer. This patch series does exactly that, as well as adjusting how we read the kernel text section to avoid the use of a bounce buffer in this case as well. This has been tested against the test case which motivated Baoquan's changes in the first place [2] which continues to function correctly, as do the vmalloc self tests. This patch (of 4): Commit df04abfd181a ("fs/proc/kcore.c: Add bounce buffer for ktext data") introduced the use of a bounce buffer to retrieve kernel text data for /proc/kcore in order to avoid failures arising from hardened user copies enabled by CONFIG_HARDENED_USERCOPY in check_kernel_text_object(). We can avoid doing this if instead of copy_to_user() we use _copy_to_user() which bypasses the hardening check. This is more efficient than using a bounce buffer and simplifies the code. We do so as part an overall effort to eliminate bounce buffer usage in the function with an eye to converting it an iterator read. Link: https://lkml.kernel.org/r/cover.1679566220.git.lstoakes@gmail.com Link: https://lore.kernel.org/all/Y8WfDSRkc%2FOHP3oD@casper.infradead.org/ [1] Link: https://lore.kernel.org/all/87ilk6gos2.fsf@oracle.com/T/#u [2] Link: https://lkml.kernel.org/r/fd39b0bfa7edc76d360def7d034baaee71d90158.1679511146.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Liu Shixin <liushixin2@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: 3d5854d75e31 ("fs/proc/kcore.c: allow translation of physical memory addresses") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-08mm: remove kern_addr_valid() completelyKefeng Wang1-17/+9
[ Upstream commit e025ab842ec35225b1a8e163d1f311beb9e38ce9 ] Most architectures (except arm64/x86/sparc) simply return 1 for kern_addr_valid(), which is only used in read_kcore(), and it calls copy_from_kernel_nofault() which could check whether the address is a valid kernel address. So as there is no need for kern_addr_valid(), let's remove it. Link: https://lkml.kernel.org/r/20221018074014.185687-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Acked-by: Heiko Carstens <hca@linux.ibm.com> [s390] Acked-by: Christoph Hellwig <hch@lst.de> Acked-by: Helge Deller <deller@gmx.de> [parisc] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: Guo Ren <guoren@kernel.org> [csky] Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: <aou@eecs.berkeley.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Chris Zankel <chris@zankel.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Jonas Bonn <jonas@southpole.se> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@rivosinc.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Will Deacon <will@kernel.org> Cc: Xuerui Wang <kernel@xen0n.name> Cc: Yoshinori Sato <ysato@users.osdn.me> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: 3d5854d75e31 ("fs/proc/kcore.c: allow translation of physical memory addresses") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-17proc: add config & param to block forcing mem writesAdrian Ratiu1-1/+60
[ Upstream commit 41e8149c8892ed1962bd15350b3c3e6e90cba7f4 ] This adds a Kconfig option and boot param to allow removing the FOLL_FORCE flag from /proc/pid/mem write calls because it can be abused. The traditional forcing behavior is kept as default because it can break GDB and some other use cases. Previously we tried a more sophisticated approach allowing distributions to fine-tune /proc/pid/mem behavior, however that got NAK-ed by Linus [1], who prefers this simpler approach with semantics also easier to understand for users. Link: https://lore.kernel.org/lkml/CAHk-=wiGWLChxYmUA5HrT5aopZrB7_2VTa0NLZcxORgkUe5tEQ@mail.gmail.com/ [1] Cc: Doug Anderson <dianders@chromium.org> Cc: Jeff Xu <jeffxu@google.com> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com> Link: https://lore.kernel.org/r/20240802080225.89408-1-adrian.ratiu@collabora.com Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-11sysctl: always initialize i_uid/i_gidThomas Weißschuh1-4/+2
[ Upstream commit 98ca62ba9e2be5863c7d069f84f7166b45a5b2f4 ] Always initialize i_uid/i_gid inside the sysfs core so set_ownership() can safely skip setting them. Commit 5ec27ec735ba ("fs/proc/proc_sysctl.c: fix the default values of i_uid/i_gid on /proc/sys inodes.") added defaults for i_uid/i_gid when set_ownership() was not implemented. It also missed adjusting net_ctl_set_ownership() to use the same default values in case the computation of a better value failed. Fixes: 5ec27ec735ba ("fs/proc/proc_sysctl.c: fix the default values of i_uid/i_gid on /proc/sys inodes.") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Joel Granados <j.granados@samsung.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-11sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table)Thomas Weißschuh1-1/+1
[ Upstream commit 520713a93d550406dae14d49cdb8778d70cecdfd ] Remove the 'table' argument from set_ownership as it is never used. This change is a step towards putting "struct ctl_table" into .rodata and eventually having sysctl core only use "const struct ctl_table". The patch was created with the following coccinelle script: @@ identifier func, head, table, uid, gid; @@ void func( struct ctl_table_header *head, - struct ctl_table *table, kuid_t *uid, kgid_t *gid) { ... } No additional occurrences of 'set_ownership' were found after doing a tree-wide search. Reviewed-by: Joel Granados <j.granados@samsung.com> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Joel Granados <j.granados@samsung.com> Stable-dep-of: 98ca62ba9e2b ("sysctl: always initialize i_uid/i_gid") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03fs/proc/task_mmu: indicate PM_FILE for PMD-mapped file THPDavid Hildenbrand1-0/+2
[ Upstream commit 3f9f022e975d930709848a86a1c79775b0585202 ] Patch series "fs/proc: move page_mapcount() to fs/proc/internal.h". With all other page_mapcount() users in the tree gone, move page_mapcount() to fs/proc/internal.h, rename it and extend the documentation to prevent future (ab)use. ... of course, I find some issues while working on that code that I sort first ;) We'll now only end up calling page_mapcount() [now folio_precise_page_mapcount()] on pages mapped via present page table entries. Except for /proc/kpagecount, that still does questionable things, but we'll leave that legacy interface as is for now. Did a quick sanity check. Likely we would want some better selfestest for /proc/$/pagemap + smaps. I'll see if I can find some time to write some more. This patch (of 6): Looks like we never taught pagemap_pmd_range() about the existence of PMD-mapped file THPs. Seems to date back to the times when we first added support for non-anon THPs in the form of shmem THP. Link: https://lkml.kernel.org/r/20240607122357.115423-1-david@redhat.com Link: https://lkml.kernel.org/r/20240607122357.115423-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Fixes: 800d8c63b2e9 ("shmem: add huge pages support") Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Lance Yang <ioworker0@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-21fs/proc: fix softlockup in __read_vmcoreRik van Riel1-0/+2
commit 5cbcb62dddf5346077feb82b7b0c9254222d3445 upstream. While taking a kernel core dump with makedumpfile on a larger system, softlockup messages often appear. While softlockup warnings can be harmless, they can also interfere with things like RCU freeing memory, which can be problematic when the kdump kexec image is configured with as little memory as possible. Avoid the softlockup, and give things like work items and RCU a chance to do their thing during __read_vmcore by adding a cond_resched. Link: https://lkml.kernel.org/r/20240507091858.36ff767f@imladris.surriel.com Signed-off-by: Rik van Riel <riel@surriel.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-15fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children statsOleg Nesterov1-26/+32
[ Upstream commit 7601df8031fd67310af891897ef6cc0df4209305 ] lock_task_sighand() can trigger a hard lockup. If NR_CPUS threads call do_task_stat() at the same time and the process has NR_THREADS, it will spin with irqs disabled O(NR_CPUS * NR_THREADS) time. Change do_task_stat() to use sig->stats_lock to gather the statistics outside of ->siglock protected section, in the likely case this code will run lockless. Link: https://lkml.kernel.org/r/20240123153357.GA21857@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Dylan Hatch <dylanbhatch@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-15fs/proc: do_task_stat: use __for_each_thread()Oleg Nesterov1-3/+4
[ Upstream commit 7904e53ed5a20fc678c01d5d1b07ec486425bb6a ] do/while_each_thread should be avoided when possible. Link: https://lkml.kernel.org/r/20230909164501.GA11581@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: 7601df8031fd ("fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-02-23fs/proc: do_task_stat: move thread_group_cputime_adjusted() outside of ↵Oleg Nesterov1-4/+6
lock_task_sighand() commit 60f92acb60a989b14e4b744501a0df0f82ef30a3 upstream. Patch series "fs/proc: do_task_stat: use sig->stats_". do_task_stat() has the same problem as getrusage() had before "getrusage: use sig->stats_lock rather than lock_task_sighand()": a hard lockup. If NR_CPUS threads call lock_task_sighand() at the same time and the process has NR_THREADS, spin_lock_irq will spin with irqs disabled O(NR_CPUS * NR_THREADS) time. This patch (of 3): thread_group_cputime() does its own locking, we can safely shift thread_group_cputime_adjusted() which does another for_each_thread loop outside of ->siglock protected section. Not only this removes for_each_thread() from the critical section with irqs disabled, this removes another case when stats_lock is taken with siglock held. We want to remove this dependency, then we can change the users of stats_lock to not disable irqs. Link: https://lkml.kernel.org/r/20240123153313.GA21832@redhat.com Link: https://lkml.kernel.org/r/20240123153355.GA21854@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Dylan Hatch <dylanbhatch@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28watchdog: move softlockup_panic back to early_paramKrister Johansen1-1/+0
commit 8b793bcda61f6c3ed4f5b2ded7530ef6749580cb upstream. Setting softlockup_panic from do_sysctl_args() causes it to take effect later in boot. The lockup detector is enabled before SMP is brought online, but do_sysctl_args runs afterwards. If a user wants to set softlockup_panic on boot and have it trigger should a softlockup occur during onlining of the non-boot processors, they could do this prior to commit f117955a2255 ("kernel/watchdog.c: convert {soft/hard}lockup boot parameters to sysctl aliases"). However, after this commit the value of softlockup_panic is set too late to be of help for this type of problem. Restore the prior behavior. Signed-off-by: Krister Johansen <kjlx@templeofstupid.com> Cc: stable@vger.kernel.org Fixes: f117955a2255 ("kernel/watchdog.c: convert {soft/hard}lockup boot parameters to sysctl aliases") Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28proc: sysctl: prevent aliased sysctls from getting passed to initKrister Johansen1-0/+7
commit 8001f49394e353f035306a45bcf504f06fca6355 upstream. The code that checks for unknown boot options is unaware of the sysctl alias facility, which maps bootparams to sysctl values. If a user sets an old value that has a valid alias, a message about an invalid parameter will be printed during boot, and the parameter will get passed to init. Fix by checking for the existence of aliased parameters in the unknown boot parameter code. If an alias exists, don't return an error or pass the value to init. Signed-off-by: Krister Johansen <kjlx@templeofstupid.com> Cc: stable@vger.kernel.org Fixes: 0a477e1ae21b ("kernel/sysctl: support handling command line aliases") Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-06proc: nommu: fix empty /proc/<pid>/mapsBen Wolsieffer2-17/+22
[ Upstream commit fe4419801617514765974f3e796269bc512ad146 ] On no-MMU, /proc/<pid>/maps reads as an empty file. This happens because find_vma(mm, 0) always returns NULL (assuming no vma actually contains the zero address, which is normally the case). To fix this bug and improve the maintainability in the future, this patch makes the no-MMU implementation as similar as possible to the MMU implementation. The only remaining differences are the lack of hold/release_task_mempolicy and the extra code to shoehorn the gate vma into the iterator. This has been tested on top of 6.5.3 on an STM32F746. Link: https://lkml.kernel.org/r/20230915160055.971059-2-ben.wolsieffer@hefring.com Fixes: 0c563f148043 ("proc: remove VMA rbtree use from nommu") Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Giulio Benetti <giulio.benetti@benettiengineering.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-06proc: nommu: /proc/<pid>/maps: release mmap read lockBen Wolsieffer1-12/+15
[ Upstream commit 578d7699e5c2add8c2e9549d9d75dfb56c460cb3 ] The no-MMU implementation of /proc/<pid>/map doesn't normally release the mmap read lock, because it uses !IS_ERR_OR_NULL(_vml) to determine whether to release the lock. Since _vml is NULL when the end of the mappings is reached, the lock is not released. Reading /proc/1/maps twice doesn't cause a hang because it only takes the read lock, which can be taken multiple times and therefore doesn't show any problem if the lock isn't released. Instead, you need to perform some operation that attempts to take the write lock after reading /proc/<pid>/maps. To actually reproduce the bug, compile the following code as 'proc_maps_bug': #include <stdio.h> #include <unistd.h> #include <sys/mman.h> int main(int argc, char *argv[]) { void *buf; sleep(1); buf = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); puts("mmap returned"); return 0; } Then, run: ./proc_maps_bug &; cat /proc/$!/maps; fg Without this patch, mmap() will hang and the command will never complete. This code was incorrectly adapted from the MMU implementation, which at the time released the lock in m_next() before returning the last entry. The MMU implementation has diverged further from the no-MMU version since then, so this patch brings their locking and error handling into sync, fixing the bug and hopefully avoiding similar issues in the future. Link: https://lkml.kernel.org/r/20230914163019.4050530-2-ben.wolsieffer@hefring.com Fixes: 47fecca15c09 ("fs/proc/task_nommu.c: don't use priv->task->mm") Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Giulio Benetti <giulio.benetti@benettiengineering.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: fe4419801617 ("proc: nommu: fix empty /proc/<pid>/maps") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-13procfs: block chmod on /proc/thread-self/commAleksa Sarai1-1/+2
commit ccf61486fe1e1a48e18c638d1813cda77b3c0737 upstream. Due to an oversight in commit 1b3044e39a89 ("procfs: fix pthread cross-thread naming if !PR_DUMPABLE") in switching from REG to NOD, chmod operations on /proc/thread-self/comm were no longer blocked as they are on almost all other procfs files. A very similar situation with /proc/self/environ was used to as a root exploit a long time ago, but procfs has SB_I_NOEXEC so this is simply a correctness issue. Ref: https://lwn.net/Articles/191954/ Ref: 6d76fa58b050 ("Don't allow chmod() on the /proc/<pid>/ files") Fixes: 1b3044e39a89 ("procfs: fix pthread cross-thread naming if !PR_DUMPABLE") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Message-Id: <20230713141001.27046-1-cyphar@cyphar.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03proc/vmcore: fix signedness bug in read_from_oldmem()Dan Carpenter1-1/+1
commit 641db40f3afe7998011bfabc726dba3e698f8196 upstream. The bug is the error handling: if (tmp < nr_bytes) { "tmp" can hold negative error codes but because "nr_bytes" is type size_t the negative error codes are treated as very high positive values (success). Fix this by changing "nr_bytes" to type ssize_t. The "nr_bytes" variable is used to store values between 1 and PAGE_SIZE and they can fit in ssize_t without any issue. Link: https://lkml.kernel.org/r/b55f7eed-1c65-4adc-95d1-6c7c65a54a6e@moroto.mountain Fixes: 5d8de293c224 ("vmcore: convert copy_oldmem_page() to take an iov_iter") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-05-17sysctl: clarify register_sysctl_init() base directory orderLuis Chamberlain1-4/+1
commit 228b09de936395ddd740df3522ea35ae934830d8 upstream. Relatively new docs which I added which hinted the base directories needed to be created before is wrong, remove that incorrect comment. This has been hinted before by Eric twice already [0] [1], I had just not verified that until now. Now that I've verified that updates the docs to relax the context described. [0] https://lkml.kernel.org/r/875ys0azt8.fsf@email.froward.int.ebiederm.org [1] https://lkml.kernel.org/r/87ftbiud6s.fsf@x220.int.ebiederm.org Cc: stable@vger.kernel.org # v5.17 Cc: Christian Brauner <brauner@kernel.org> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Suggested-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-05-17proc_sysctl: enhance documentationLuis Chamberlain1-5/+20
commit 1dc8689e4cc651e21566e10206a84c4006e81fb1 upstream. Expand documentation to clarify: o that paths don't need to exist for the new API callers o clarify that we *require* callers to keep the memory of the table around during the lifetime of the sysctls o annotate routines we are trying to deprecate and later remove Cc: stable@vger.kernel.org # v5.17 Cc: Christian Brauner <brauner@kernel.org> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-05-17proc_sysctl: update docs for __register_sysctl_table()Luis Chamberlain1-3/+11
commit 67ff32289acad9ed338cd9f2351b44939e55163e upstream. Update the docs for __register_sysctl_table() to make it clear no child entries can be passed. When the child is true these are non-leaf entries on the ctl table and sysctl treats these as directories. The point to __register_sysctl_table() is to deal only with directories not part of the ctl table where thay may riside, to be simple and avoid recursion. While at it, hint towards using long on extra1 and extra2 later. Cc: stable@vger.kernel.org # v5.17 Cc: Christian Brauner <brauner@kernel.org> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09mm: hugetlb: proc: check for hugetlb shared PMD in /proc/PID/smapsMike Kravetz1-3/+1
commit 3489dbb696d25602aea8c3e669a6d43b76bd5358 upstream. Patch series "Fixes for hugetlb mapcount at most 1 for shared PMDs". This issue of mapcount in hugetlb pages referenced by shared PMDs was discussed in [1]. The following two patches address user visible behavior caused by this issue. [1] https://lore.kernel.org/linux-mm/Y9BF+OCdWnCSilEu@monkey/ This patch (of 2): A hugetlb page will have a mapcount of 1 if mapped by multiple processes via a shared PMD. This is because only the first process increases the map count, and subsequent processes just add the shared PMD page to their page table. page_mapcount is being used to decide if a hugetlb page is shared or private in /proc/PID/smaps. Pages referenced via a shared PMD were incorrectly being counted as private. To fix, check for a shared PMD if mapcount is 1. If a shared PMD is found count the hugetlb page as shared. A new helper to check for a shared PMD is added. [akpm@linux-foundation.org: simplification, per David] [akpm@linux-foundation.org: hugetlb.h: include page_ref.h for page_count()] Link: https://lkml.kernel.org/r/20230126222721.222195-2-mike.kravetz@oracle.com Fixes: 25ee01a2fca0 ("mm: hugetlb: proc: add hugetlb-related fields to /proc/PID/smaps") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09use less confusing names for iov_iter direction initializersAl Viro1-3/+3
[ Upstream commit de4eda9de2d957ef2d6a8365a01e26a435e958cb ] READ/WRITE proved to be actively confusing - the meanings are "data destination, as used with read(2)" and "data source, as used with write(2)", but people keep interpreting those as "we read data from it" and "we write data to it", i.e. exactly the wrong way. Call them ITER_DEST and ITER_SOURCE - at least that is harder to misinterpret... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Stable-dep-of: 6dd88fd59da8 ("vhost-scsi: unbreak any layout for response") Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-23proc/meminfo: fix spacing in SecPageTablesYosry Ahmed1-1/+1
SecPageTables has a tab after it instead of a space, this can break fragile parsers that depend on spaces after the stat names. Link: https://lkml.kernel.org/r/20221117043247.133294-1-yosryahmed@google.com Fixes: ebc97a52b5d6cd5f ("mm: add NR_SECONDARY_PAGETABLE to count secondary page table uses.") Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Shakeel Butt <shakeelb@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-21mm: /proc/pid/smaps_rollup: fix maple tree searchHugh Dickins1-1/+1
/proc/pid/smaps_rollup showed 0 kB for everything: now find first vma. Link: https://lkml.kernel.org/r/3011bee7-182-97a2-1083-d5f5b688e54b@google.com Fixes: c4c84f06285e ("fs/proc/task_mmu: stop using linked list and highest_vm_end") Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12Merge tag 'mm-nonmm-stable-2022-10-11' of ↵Linus Torvalds9-6/+38
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: - hfs and hfsplus kmap API modernization (Fabio Francesco) - make crash-kexec work properly when invoked from an NMI-time panic (Valentin Schneider) - ntfs bugfixes (Hawkins Jiawei) - improve IPC msg scalability by replacing atomic_t's with percpu counters (Jiebin Sun) - nilfs2 cleanups (Minghao Chi) - lots of other single patches all over the tree! * tag 'mm-nonmm-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (71 commits) include/linux/entry-common.h: remove has_signal comment of arch_do_signal_or_restart() prototype proc: test how it holds up with mapping'less process mailmap: update Frank Rowand email address ia64: mca: use strscpy() is more robust and safer init/Kconfig: fix unmet direct dependencies ia64: update config files nilfs2: replace WARN_ONs by nilfs_error for checkpoint acquisition failure fork: remove duplicate included header files init/main.c: remove unnecessary (void*) conversions proc: mark more files as permanent nilfs2: remove the unneeded result variable nilfs2: delete unnecessary checks before brelse() checkpatch: warn for non-standard fixes tag style usr/gen_init_cpio.c: remove unnecessary -1 values from int file ipc/msg: mitigate the lock contention with percpu counter percpu: add percpu_counter_add_local and percpu_counter_sub_local fs/ocfs2: fix repeated words in comments relay: use kvcalloc to alloc page array in relay_alloc_page_array proc: make config PROC_CHILDREN depend on PROC_FS fs: uninline inode_maybe_inc_iversion() ...
2022-10-11Merge tag 'mm-stable-2022-10-08' of ↵Linus Torvalds4-63/+100
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...
2022-10-10Merge tag 'sysctl-6.1-rc1' of ↵Linus Torvalds1-8/+1
git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux Pull sysctl updates from Luis Chamberlain: "Just some boring cleanups on the sysctl front for this release" * tag 'sysctl-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: kernel/sysctl-test: use SYSCTL_{ZERO/ONE_HUNDRED} instead of i_{zero/one_hundred} kernel/sysctl.c: move sysctl_vals and sysctl_long_vals to sysctl.c sysctl: remove max_extfrag_threshold kernel/sysctl.c: remove unnecessary (void*) conversions proc: remove initialization assignment
2022-10-10Merge tag 'printk-for-6.1' of ↵Linus Torvalds1-2/+0
git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux Pull printk updates from Petr Mladek: - Initialize pointer hashing using the system workqueue. It avoids taking locks in printk()/vsprintf() code path - Misc code clean up * tag 'printk-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: printk: Mark __printk percpu data ready __ro_after_init printk: Remove bogus comment vs. boot consoles printk: Remove write only variable nr_ext_console_drivers printk: Declare log_wait properly printk: Make pr_flush() static lib/vsprintf: Initialize vsprintf's pointer hash once the random core is ready. lib/vsprintf: Remove static_branch_likely() from __ptr_to_hashval(). lib/vnsprintf: add const modifier for param 'bitmap'
2022-10-10Merge tag 'ucount-rlimits-cleanups-for-v5.19' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull ucounts update from Eric Biederman: "Split rlimit and ucount values and max values After the ucount rlimit code was merged a bunch of small but siginificant bugs were found and fixed. At the time it was realized that part of the problem was that while the ucount rlimits were very similar to the oridinary ucounts (in being nested counts with limits) the semantics were slightly different and the code would be less error prone if there was less sharing. This is the long awaited cleanup that should hopefully keep things more comprehensible and less error prone for whoever needs to touch that code next" * tag 'ucount-rlimits-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: ucounts: Split rlimit and ucount values and max values
2022-10-09Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-0/+2
Pull kvm updates from Paolo Bonzini: "The first batch of KVM patches, mostly covering x86. ARM: - Account stage2 page table allocations in memory stats x86: - Account EPT/NPT arm64 page table allocations in memory stats - Tracepoint cleanups/fixes for nested VM-Enter and emulated MSR accesses - Drop eVMCS controls filtering for KVM on Hyper-V, all known versions of Hyper-V now support eVMCS fields associated with features that are enumerated to the guest - Use KVM's sanitized VMCS config as the basis for the values of nested VMX capabilities MSRs - A myriad event/exception fixes and cleanups. Most notably, pending exceptions morph into VM-Exits earlier, as soon as the exception is queued, instead of waiting until the next vmentry. This fixed a longstanding issue where the exceptions would incorrecly become double-faults instead of triggering a vmexit; the common case of page-fault vmexits had a special workaround, but now it's fixed for good - A handful of fixes for memory leaks in error paths - Cleanups for VMREAD trampoline and VMX's VM-Exit assembly flow - Never write to memory from non-sleepable kvm_vcpu_check_block() - Selftests refinements and cleanups - Misc typo cleanups Generic: - remove KVM_REQ_UNHALT" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (94 commits) KVM: remove KVM_REQ_UNHALT KVM: mips, x86: do not rely on KVM_REQ_UNHALT KVM: x86: never write to memory from kvm_vcpu_check_block() KVM: x86: Don't snapshot pending INIT/SIPI prior to checking nested events KVM: nVMX: Make event request on VMXOFF iff INIT/SIPI is pending KVM: nVMX: Make an event request if INIT or SIPI is pending on VM-Enter KVM: SVM: Make an event request if INIT or SIPI is pending when GIF is set KVM: x86: lapic does not have to process INIT if it is blocked KVM: x86: Rename kvm_apic_has_events() to make it INIT/SIPI specific KVM: x86: Rename and expose helper to detect if INIT/SIPI are allowed KVM: nVMX: Make an event request when pending an MTF nested VM-Exit KVM: x86: make vendor code check for all nested events mailmap: Update Oliver's email address KVM: x86: Allow force_emulation_prefix to be written without a reload KVM: selftests: Add an x86-only test to verify nested exception queueing KVM: selftests: Use uapi header to get VMX and SVM exit reasons/codes KVM: x86: Rename inject_pending_events() to kvm_check_and_inject_events() KVM: VMX: Update MTF and ICEBP comments to document KVM's subtle behavior KVM: x86: Treat pending TRIPLE_FAULT requests as pending exceptions KVM: x86: Morph pending exceptions to pending VM-Exits at queue time ...
2022-10-07Merge tag 'pull-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-2/+2
Pull vfs constification updates from Al Viro: "whack-a-mole: constifying struct path *" * tag 'pull-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: ecryptfs: constify path spufs: constify path nd_jump_link(): constify path audit_init_parent(): constify path __io_setxattr(): constify path do_proc_readlink(): constify path overlayfs: constify path fs/notify: constify path may_linkat(): constify path do_sys_name_to_handle(): constify path ->getprocattr(): attribute name is const char *, TYVM...
2022-10-04Merge branch 'rework/kthreads' into for-linusPetr Mladek1-2/+0
2022-10-04proc: mark more files as permanentAlexey Dobriyan8-6/+37
Mark /proc/devices /proc/kpagecount /proc/kpageflags /proc/kpagecgroup /proc/loadavg /proc/meminfo /proc/softirqs /proc/uptime /proc/version as permanent /proc entries, saving alloc/free and some list/spinlock ops per use. These files are never removed by the kernel so it is OK to mark them. Link: https://lkml.kernel.org/r/Yyn527DzDMa+r0Yj@localhost.localdomain Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-04proc: make config PROC_CHILDREN depend on PROC_FSLukas Bulwahn1-0/+1
Commit 2e13ba54a268 ("fs, proc: introduce CONFIG_PROC_CHILDREN") introduces the config PROC_CHILDREN to configure kernels to provide the /proc/<pid>/task/<tid>/children file. When one deselects PROC_FS for kernel builds without /proc/, the config PROC_CHILDREN has no effect anymore, but is still visible in menuconfig. Add the dependency on PROC_FS to make the PROC_CHILDREN option disappear for kernel builds without /proc/. Link: https://lkml.kernel.org/r/20220909122529.1941-1-lukas.bulwahn@gmail.com Fixes: 2e13ba54a268 ("fs, proc: introduce CONFIG_PROC_CHILDREN") Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Iago López Galeiras <iago@endocode.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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