kernel/linux.git/fs/ceph/dir.c, branch v6.19.11

ceph: add a bunch of missing ceph_path_info initializers

2026-03-19T15:15:10+00:00

commit 43323a5934b660afae687e8e4e95ac328615a5c4 upstream. ceph_mdsc_build_path() must be called with a zero-initialized ceph_path_info parameter, or else the following ceph_mdsc_free_path_info() may crash. Example crash (on Linux 6.18.12): virt_to_cache: Object is not a Slab page! WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6732 kmem_cache_free+0x316/0x400 [...] Call Trace: [...] ceph_open+0x13d/0x3e0 do_dentry_open+0x134/0x480 vfs_open+0x2a/0xe0 path_openat+0x9a3/0x1160 [...] cache_from_obj: Wrong slab cache. names_cache but object is from ceph_inode_info WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6746 kmem_cache_free+0x2dd/0x400 [...] kernel BUG at mm/slub.c:634! Oops: invalid opcode: 0000 [#1] SMP NOPTI RIP: 0010:__slab_free+0x1a4/0x350 Some of the ceph_mdsc_build_path() callers had initializers, but others had not, even though they were all added by commit 15f519e9f883 ("ceph: fix race condition validating r_parent before applying state"). The ones without initializer are suspectible to random crashes. (I can imagine it could even be possible to exploit this bug to elevate privileges.) Unfortunately, these Ceph functions are undocumented and its semantics can only be derived from the code. I see that ceph_mdsc_build_path() initializes the structure only on success, but not on error. Calling ceph_mdsc_free_path_info() after a failed ceph_mdsc_build_path() call does not even make sense, but that's what all callers do, and for it to be safe, the structure must be zero-initialized. The least intrusive approach to fix this is therefore to add initializers everywhere. Cc: stable@vger.kernel.org Fixes: 15f519e9f883 ("ceph: fix race condition validating r_parent before applying state") Signed-off-by: Max Kellermann Reviewed-by: Viacheslav Dubeyko Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman

ceph: fix i_nlink underrun during async unlink

2026-03-19T15:15:07+00:00

commit ce0123cbb4a40a2f1bbb815f292b26e96088639f upstream. During async unlink, we drop the `i_nlink` counter before we receive the completion (that will eventually update the `i_nlink`) because "we assume that the unlink will succeed". That is not a bad idea, but it races against deletions by other clients (or against the completion of our own unlink) and can lead to an underrun which emits a WARNING like this one: WARNING: CPU: 85 PID: 25093 at fs/inode.c:407 drop_nlink+0x50/0x68 Modules linked in: CPU: 85 UID: 3221252029 PID: 25093 Comm: php-cgi8.1 Not tainted 6.14.11-cm4all1-ampere #655 Hardware name: Supermicro ARS-110M-NR/R12SPD-A, BIOS 1.1b 10/17/2023 pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : drop_nlink+0x50/0x68 lr : ceph_unlink+0x6c4/0x720 sp : ffff80012173bc90 x29: ffff80012173bc90 x28: ffff086d0a45aaf8 x27: ffff0871d0eb5680 x26: ffff087f2a64a718 x25: 0000020000000180 x24: 0000000061c88647 x23: 0000000000000002 x22: ffff07ff9236d800 x21: 0000000000001203 x20: ffff07ff9237b000 x19: ffff088b8296afc0 x18: 00000000f3c93365 x17: 0000000000070000 x16: ffff08faffcbdfe8 x15: ffff08faffcbdfec x14: 0000000000000000 x13: 45445f65645f3037 x12: 34385f6369706f74 x11: 0000a2653104bb20 x10: ffffd85f26d73290 x9 : ffffd85f25664f94 x8 : 00000000000000c0 x7 : 0000000000000000 x6 : 0000000000000002 x5 : 0000000000000081 x4 : 0000000000000481 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff08727d3f91e8 Call trace: drop_nlink+0x50/0x68 (P) vfs_unlink+0xb0/0x2e8 do_unlinkat+0x204/0x288 __arm64_sys_unlinkat+0x3c/0x80 invoke_syscall.constprop.0+0x54/0xe8 do_el0_svc+0xa4/0xc8 el0_svc+0x18/0x58 el0t_64_sync_handler+0x104/0x130 el0t_64_sync+0x154/0x158 In ceph_unlink(), a call to ceph_mdsc_submit_request() submits the CEPH_MDS_OP_UNLINK to the MDS, but does not wait for completion. Meanwhile, between this call and the following drop_nlink() call, a worker thread may process a CEPH_CAP_OP_IMPORT, CEPH_CAP_OP_GRANT or just a CEPH_MSG_CLIENT_REPLY (the latter of which could be our own completion). These will lead to a set_nlink() call, updating the `i_nlink` counter to the value received from the MDS. If that new `i_nlink` value happens to be zero, it is illegal to decrement it further. But that is exactly what ceph_unlink() will do then. The WARNING can be reproduced this way: 1. Force async unlink; only the async code path is affected. Having no real clue about Ceph internals, I was unable to find out why the MDS wouldn't give me the "Fxr" capabilities, so I patched get_caps_for_async_unlink() to always succeed. (Note that the WARNING dump above was found on an unpatched kernel, without this kludge - this is not a theoretical bug.) 2. Add a sleep call after ceph_mdsc_submit_request() so the unlink completion gets handled by a worker thread before drop_nlink() is called. This guarantees that the `i_nlink` is already zero before drop_nlink() runs. The solution is to skip the counter decrement when it is already zero, but doing so without a lock is still racy (TOCTOU). Since ceph_fill_inode() and handle_cap_grant() both hold the `ceph_inode_info.i_ceph_lock` spinlock while set_nlink() runs, this seems like the proper lock to protect the `i_nlink` updates. I found prior art in NFS and SMB (using `inode.i_lock`) and AFS (using `afs_vnode.cb_lock`). All three have the zero check as well. Cc: stable@vger.kernel.org Fixes: 2ccb45462aea ("ceph: perform asynchronous unlink if we have sufficient caps") Signed-off-by: Max Kellermann Reviewed-by: Viacheslav Dubeyko Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman

ceph: don't allow delegations to be set on directories

2026-01-12T09:54:47+00:00

With the advent of directory leases, it's necessary to set the ->setlease() handler in directory file_operations to properly deny them. Fixes: e6d28ebc17eb ("filelock: push the S_ISREG check down to ->setlease handlers") Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20260107-setlease-6-19-v1-5-85f034abcc57@kernel.org Reviewed-by: Viacheslav Dubeyko Signed-off-by: Christian Brauner

Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-12-06T22:01:20+00:00

Pull non-MM updates from Andrew Morton: - "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko) fixes a build issue and does some cleanup in ib/sys_info.c - "Implement mul_u64_u64_div_u64_roundup()" (David Laight) enhances the 64-bit math code on behalf of a PWM driver and beefs up the test module for these library functions - "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich) makes BPF symbol names, sizes, and line numbers available to the GDB debugger - "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang) adds a sysctl which can be used to cause additional info dumping when the hung-task and lockup detectors fire - "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu) adds a general base64 encoder/decoder to lib/ and migrates several users away from their private implementations - "rbree: inline rb_first() and rb_last()" (Eric Dumazet) makes TCP a little faster - "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin) reworks the KEXEC Handover interfaces in preparation for Live Update Orchestrator (LUO), and possibly for other future clients - "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin) increases the flexibility of KEXEC Handover. Also preparation for LUO - "Live Update Orchestrator" (Pasha Tatashin) is a major new feature targeted at cloud environments. Quoting the cover letter: This series introduces the Live Update Orchestrator, a kernel subsystem designed to facilitate live kernel updates using a kexec-based reboot. This capability is critical for cloud environments, allowing hypervisors to be updated with minimal downtime for running virtual machines. LUO achieves this by preserving the state of selected resources, such as memory, devices and their dependencies, across the kernel transition. As a key feature, this series includes support for preserving memfd file descriptors, which allows critical in-memory data, such as guest RAM or any other large memory region, to be maintained in RAM across the kexec reboot. Mike Rappaport merits a mention here, for his extensive review and testing work. - "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain) moves the kexec and kdump sysfs entries from /sys/kernel/ to /sys/kernel/kexec/ and adds back-compatibility symlinks which can hopefully be removed one day - "kho: fixes for vmalloc restoration" (Mike Rapoport) fixes a BUG which was being hit during KHO restoration of vmalloc() regions * tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits) calibrate: update header inclusion Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()" vmcoreinfo: track and log recoverable hardware errors kho: fix restoring of contiguous ranges of order-0 pages kho: kho_restore_vmalloc: fix initialization of pages array MAINTAINERS: TPM DEVICE DRIVER: update the W-tag init: replace simple_strtoul with kstrtoul to improve lpj_setup KHO: fix boot failure due to kmemleak access to non-PRESENT pages Documentation/ABI: new kexec and kdump sysfs interface Documentation/ABI: mark old kexec sysfs deprecated kexec: move sysfs entries to /sys/kernel/kexec test_kho: always print restore status kho: free chunks using free_page() instead of kfree() selftests/liveupdate: add kexec test for multiple and empty sessions selftests/liveupdate: add simple kexec-based selftest for LUO selftests/liveupdate: add userspace API selftests docs: add documentation for memfd preservation via LUO mm: memfd_luo: allow preserving memfd liveupdate: luo_file: add private argument to store runtime state mm: shmem: export some functions to internal.h ...

Merge tag 'printk-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2025-12-03T20:42:36+00:00

Pull printk updates from Petr Mladek: - Allow creaing nbcon console drivers with an unsafe write_atomic() callback that can only be called by the final nbcon_atomic_flush_unsafe(). Otherwise, the driver would rely on the kthread. It is going to be used as the-best-effort approach for an experimental nbcon netconsole driver, see https://lore.kernel.org/r/20251121-nbcon-v1-2-503d17b2b4af@debian.org Note that a safe .write_atomic() callback is supposed to work in NMI context. But some networking drivers are not safe even in IRQ context: https://lore.kernel.org/r/oc46gdpmmlly5o44obvmoatfqo5bhpgv7pabpvb6sjuqioymcg@gjsma3ghoz35 In an ideal world, all networking drivers would be fixed first and the atomic flush would be blocked only in NMI context. But it brings the question how reliable networking drivers are when the system is in a bad state. They might block flushing more reliable serial consoles which are more suitable for serious debugging anyway. - Allow to use the last 4 bytes of the printk ring buffer. - Prevent queuing IRQ work and block printk kthreads when consoles are suspended. Otherwise, they create non-necessary churn or even block the suspend. - Release console_lock() between each record in the kthread used for legacy consoles on RT. It might significantly speed up the boot. - Release nbcon context between each record in the atomic flush. It prevents stalls of the related printk kthread after it has lost the ownership in the middle of a record - Add support for NBCON consoles into KDB - Add %ptsP modifier for printing struct timespec64 and use it where possible - Misc code clean up * tag 'printk-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (48 commits) printk: Use console_is_usable on console_unblank arch: um: kmsg_dump: Use console_is_usable drivers: serial: kgdboc: Drop checks for CON_ENABLED and CON_BOOT lib/vsprintf: Unify FORMAT_STATE_NUM handlers printk: Avoid irq_work for printk_deferred() on suspend printk: Avoid scheduling irq_work on suspend printk: Allow printk_trigger_flush() to flush all types tracing: Switch to use %ptSp scsi: snic: Switch to use %ptSp scsi: fnic: Switch to use %ptSp s390/dasd: Switch to use %ptSp ptp: ocp: Switch to use %ptSp pps: Switch to use %ptSp PCI: epf-test: Switch to use %ptSp net: dsa: sja1105: Switch to use %ptSp mmc: mmc_test: Switch to use %ptSp media: av7110: Switch to use %ptSp ipmi: Switch to use %ptSp igb: Switch to use %ptSp e1000e: Switch to use %ptSp ...

ceph: replace local base64 helpers with lib/base64

2025-11-20T22:03:44+00:00

Remove the ceph_base64_encode() and ceph_base64_decode() functions and replace their usage with the generic base64_encode() and base64_decode() helpers from lib/base64. This eliminates the custom implementation in Ceph, reduces code duplication, and relies on the shared Base64 code in lib. The helpers preserve RFC 3501-compliant Base64 encoding without padding, so there are no functional changes. This change also improves performance: encoding is about 2.7x faster and decoding achieves 43-52x speedups compared to the previous local implementation. Link: https://lkml.kernel.org/r/20251114060240.89965-1-409411716@gms.tku.edu.tw Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw> Reviewed-by: Kuan-Wei Chiu Reviewed-by: Viacheslav Dubeyko Cc: Keith Busch Cc: Jens Axboe Cc: Christoph Hellwig Cc: Sagi Grimberg Cc: Xiubo Li Cc: Ilya Dryomov Cc: Eric Biggers Cc: "Theodore Y. Ts'o" Cc: Jaegeuk Kim Cc: David Laight Cc: Yu-Sheng Huang Signed-off-by: Andrew Morton

ceph: Switch to use %ptSp

2025-11-19T09:24:13+00:00

Use %ptSp instead of open coded variants to print content of struct timespec64 in human readable format. Reviewed-by: Viacheslav Dubeyko Signed-off-by: Andy Shevchenko Link: https://patch.msgid.link/20251113150217.3030010-3-andriy.shevchenko@linux.intel.com Signed-off-by: Petr Mladek

ceph: refactor wake_up_bit() pattern of calling

2025-10-08T21:30:46+00:00

The wake_up_bit() is called in ceph_async_unlink_cb(), wake_async_create_waiters(), and ceph_finish_async_create(). It makes sense to switch on clear_bit() function, because it makes the code much cleaner and easier to understand. More important rework is the adding of smp_mb__after_atomic() memory barrier after the bit modification and before wake_up_bit() call. It can prevent potential race condition of accessing the modified bit in other threads. Luckily, clear_and_wake_up_bit() already implements the required functionality pattern: static inline void clear_and_wake_up_bit(int bit, unsigned long *word) { clear_bit_unlock(bit, word); /* See wake_up_bit() for which memory barrier you need to use. */ smp_mb__after_atomic(); wake_up_bit(word, bit); } Signed-off-by: Viacheslav Dubeyko Reviewed-by: Alex Markuze Signed-off-by: Ilya Dryomov

ceph: fix race condition validating r_parent before applying state

2025-09-09T10:57:02+00:00

Add validation to ensure the cached parent directory inode matches the directory info in MDS replies. This prevents client-side race conditions where concurrent operations (e.g. rename) cause r_parent to become stale between request initiation and reply processing, which could lead to applying state changes to incorrect directory inodes. [ idryomov: folded a kerneldoc fixup and a follow-up fix from Alex to move CEPH_CAP_PIN reference when r_parent is updated: When the parent directory lock is not held, req->r_parent can become stale and is updated to point to the correct inode. However, the associated CEPH_CAP_PIN reference was not being adjusted. The CEPH_CAP_PIN is a reference on an inode that is tracked for accounting purposes. Moving this pin is important to keep the accounting balanced. When the pin was not moved from the old parent to the new one, it created two problems: The reference on the old, stale parent was never released, causing a reference leak. A reference for the new parent was never acquired, creating the risk of a reference underflow later in ceph_mdsc_release_request(). This patch corrects the logic by releasing the pin from the old parent and acquiring it for the new parent when r_parent is switched. This ensures reference accounting stays balanced. ] Cc: stable@vger.kernel.org Signed-off-by: Alex Markuze Reviewed-by: Viacheslav Dubeyko Signed-off-by: Ilya Dryomov

ceph: fix a race with rename() in ceph_mdsc_build_path()

2025-06-17T21:58:14+00:00

Lift copying the name into callers of ceph_encode_encrypted_dname() that do not have it already copied; ceph_encode_encrypted_fname() disappears. That fixes a UAF in ceph_mdsc_build_path() - while the initial copy of plaintext into buf is done under ->d_lock, we access the original name again in ceph_encode_encrypted_fname() and that is done without any locking. With ceph_encode_encrypted_dname() using the stable copy the problem goes away. Tested-by: Viacheslav Dubeyko Reviewed-by: Viacheslav Dubeyko Signed-off-by: Al Viro