ghsa-p8xq-m5g2-cvrc
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
NFS: Fix nfs_netfs_issue_read() xarray locking for writeback interrupt
The loop inside nfs_netfs_issue_read() currently does not disable interrupts while iterating through pages in the xarray to submit for NFS read. This is not safe though since after taking xa_lock, another page in the mapping could be processed for writeback inside an interrupt, and deadlock can occur. The fix is simple and clean if we use xa_for_each_range(), which handles the iteration with RCU while reducing code complexity.
The problem is easily reproduced with the following test: mount -o vers=3,fsc 127.0.0.1:/export /mnt/nfs dd if=/dev/zero of=/mnt/nfs/file1.bin bs=4096 count=1 echo 3 > /proc/sys/vm/drop_caches dd if=/mnt/nfs/file1.bin of=/dev/null umount /mnt/nfs
On the console with a lockdep-enabled kernel a message similar to the following will be seen:
================================ WARNING: inconsistent lock state 6.7.0-lockdbg+ #10 Not tainted
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
test5/1708 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffff888127baa598 (&xa->xa_lock#4){+.?.}-{3:3}, at:
nfs_netfs_issue_read+0x1b2/0x4b0 [nfs]
{IN-SOFTIRQ-W} state was registered at:
lock_acquire+0x144/0x380
_raw_spin_lock_irqsave+0x4e/0xa0
__folio_end_writeback+0x17e/0x5c0
folio_end_writeback+0x93/0x1b0
iomap_finish_ioend+0xeb/0x6a0
blk_update_request+0x204/0x7f0
blk_mq_end_request+0x30/0x1c0
blk_complete_reqs+0x7e/0xa0
__do_softirq+0x113/0x544
__irq_exit_rcu+0xfe/0x120
irq_exit_rcu+0xe/0x20
sysvec_call_function_single+0x6f/0x90
asm_sysvec_call_function_single+0x1a/0x20
pv_native_safe_halt+0xf/0x20
default_idle+0x9/0x20
default_idle_call+0x67/0xa0
do_idle+0x2b5/0x300
cpu_startup_entry+0x34/0x40
start_secondary+0x19d/0x1c0
secondary_startup_64_no_verify+0x18f/0x19b
irq event stamp: 176891
hardirqs last enabled at (176891): [
other info that might help us debug this: Possible unsafe locking scenario:
CPU0
----
lock(&xa->xa_lock#4);
*** DEADLOCK ***
2 locks held by test5/1708: #0: ffff888127baa498 (&sb->s_type->i_mutex_key#22){++++}-{4:4}, at: nfs_start_io_read+0x28/0x90 [nfs] #1: ffff888127baa650 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: page_cache_ra_unbounded+0xa4/0x280
stack backtrace: CPU: 6 PID: 1708 Comm: test5 Kdump: loaded Not tainted 6.7.0-lockdbg+ Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39 04/01/2014 Call Trace: dump_stack_lvl+0x5b/0x90 mark_lock+0xb3f/0xd20 __lock_acquire+0x77b/0x3360 _raw_spin_lock+0x34/0x80 nfs_netfs_issue_read+0x1b2/0x4b0 [nfs] netfs_begin_read+0x77f/0x980 [netfs] nfs_netfs_readahead+0x45/0x60 [nfs] nfs_readahead+0x323/0x5a0 [nfs] read_pages+0xf3/0x5c0 page_cache_ra_unbounded+0x1c8/0x280 filemap_get_pages+0x38c/0xae0 filemap_read+0x206/0x5e0 nfs_file_read+0xb7/0x140 [nfs] vfs_read+0x2a9/0x460 ksys_read+0xb7/0x140
{
"affected": [],
"aliases": [
"CVE-2024-27031"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-01T13:15:49Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFS: Fix nfs_netfs_issue_read() xarray locking for writeback interrupt\n\nThe loop inside nfs_netfs_issue_read() currently does not disable\ninterrupts while iterating through pages in the xarray to submit\nfor NFS read. This is not safe though since after taking xa_lock,\nanother page in the mapping could be processed for writeback inside\nan interrupt, and deadlock can occur. The fix is simple and clean\nif we use xa_for_each_range(), which handles the iteration with RCU\nwhile reducing code complexity.\n\nThe problem is easily reproduced with the following test:\n mount -o vers=3,fsc 127.0.0.1:/export /mnt/nfs\n dd if=/dev/zero of=/mnt/nfs/file1.bin bs=4096 count=1\n echo 3 \u003e /proc/sys/vm/drop_caches\n dd if=/mnt/nfs/file1.bin of=/dev/null\n umount /mnt/nfs\n\nOn the console with a lockdep-enabled kernel a message similar to\nthe following will be seen:\n\n ================================\n WARNING: inconsistent lock state\n 6.7.0-lockdbg+ #10 Not tainted\n --------------------------------\n inconsistent {IN-SOFTIRQ-W} -\u003e {SOFTIRQ-ON-W} usage.\n test5/1708 [HC0[0]:SC0[0]:HE1:SE1] takes:\n ffff888127baa598 (\u0026xa-\u003exa_lock#4){+.?.}-{3:3}, at:\nnfs_netfs_issue_read+0x1b2/0x4b0 [nfs]\n {IN-SOFTIRQ-W} state was registered at:\n lock_acquire+0x144/0x380\n _raw_spin_lock_irqsave+0x4e/0xa0\n __folio_end_writeback+0x17e/0x5c0\n folio_end_writeback+0x93/0x1b0\n iomap_finish_ioend+0xeb/0x6a0\n blk_update_request+0x204/0x7f0\n blk_mq_end_request+0x30/0x1c0\n blk_complete_reqs+0x7e/0xa0\n __do_softirq+0x113/0x544\n __irq_exit_rcu+0xfe/0x120\n irq_exit_rcu+0xe/0x20\n sysvec_call_function_single+0x6f/0x90\n asm_sysvec_call_function_single+0x1a/0x20\n pv_native_safe_halt+0xf/0x20\n default_idle+0x9/0x20\n default_idle_call+0x67/0xa0\n do_idle+0x2b5/0x300\n cpu_startup_entry+0x34/0x40\n start_secondary+0x19d/0x1c0\n secondary_startup_64_no_verify+0x18f/0x19b\n irq event stamp: 176891\n hardirqs last enabled at (176891): [\u003cffffffffa67a0be4\u003e]\n_raw_spin_unlock_irqrestore+0x44/0x60\n hardirqs last disabled at (176890): [\u003cffffffffa67a0899\u003e]\n_raw_spin_lock_irqsave+0x79/0xa0\n softirqs last enabled at (176646): [\u003cffffffffa515d91e\u003e]\n__irq_exit_rcu+0xfe/0x120\n softirqs last disabled at (176633): [\u003cffffffffa515d91e\u003e]\n__irq_exit_rcu+0xfe/0x120\n\n other info that might help us debug this:\n Possible unsafe locking scenario:\n\n CPU0\n ----\n lock(\u0026xa-\u003exa_lock#4);\n \u003cInterrupt\u003e\n lock(\u0026xa-\u003exa_lock#4);\n\n *** DEADLOCK ***\n\n 2 locks held by test5/1708:\n #0: ffff888127baa498 (\u0026sb-\u003es_type-\u003ei_mutex_key#22){++++}-{4:4}, at:\n nfs_start_io_read+0x28/0x90 [nfs]\n #1: ffff888127baa650 (mapping.invalidate_lock#3){.+.+}-{4:4}, at:\n page_cache_ra_unbounded+0xa4/0x280\n\n stack backtrace:\n CPU: 6 PID: 1708 Comm: test5 Kdump: loaded Not tainted 6.7.0-lockdbg+\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39\n04/01/2014\n Call Trace:\n dump_stack_lvl+0x5b/0x90\n mark_lock+0xb3f/0xd20\n __lock_acquire+0x77b/0x3360\n _raw_spin_lock+0x34/0x80\n nfs_netfs_issue_read+0x1b2/0x4b0 [nfs]\n netfs_begin_read+0x77f/0x980 [netfs]\n nfs_netfs_readahead+0x45/0x60 [nfs]\n nfs_readahead+0x323/0x5a0 [nfs]\n read_pages+0xf3/0x5c0\n page_cache_ra_unbounded+0x1c8/0x280\n filemap_get_pages+0x38c/0xae0\n filemap_read+0x206/0x5e0\n nfs_file_read+0xb7/0x140 [nfs]\n vfs_read+0x2a9/0x460\n ksys_read+0xb7/0x140",
"id": "GHSA-p8xq-m5g2-cvrc",
"modified": "2024-05-01T15:30:35Z",
"published": "2024-05-01T15:30:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-27031"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8a2e5977cecd3cde6a0e3e86b7b914d00240e5dc"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8df1678c021ffeb20ef8a203bd9413f3ed9b0e9a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ad27382f8495f8ef6d2c66c413d756bfd13c0598"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fd5860ab6341506004219b080aea40213b299d2e"
}
],
"schema_version": "1.4.0",
"severity": []
}