ghsa-3cvm-96rv-2mw4
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
fscache: Use wait_on_bit() to wait for the freeing of relinquished volume
The freeing of relinquished volume will wake up the pending volume acquisition by using wake_up_bit(), however it is mismatched with wait_var_event() used in fscache_wait_on_volume_collision() and it will never wake up the waiter in the wait-queue because these two functions operate on different wait-queues.
According to the implementation in fscache_wait_on_volume_collision(), if the wake-up of pending acquisition is delayed longer than 20 seconds (e.g., due to the delay of on-demand fd closing), the first wait_var_event_timeout() will timeout and the following wait_var_event() will hang forever as shown below:
FS-Cache: Potential volume collision new=00000024 old=00000022 ...... INFO: task mount:1148 blocked for more than 122 seconds. Not tainted 6.1.0-rc6+ #1 task:mount state:D stack:0 pid:1148 ppid:1 Call Trace: __schedule+0x2f6/0xb80 schedule+0x67/0xe0 fscache_wait_on_volume_collision.cold+0x80/0x82 __fscache_acquire_volume+0x40d/0x4e0 erofs_fscache_register_volume+0x51/0xe0 [erofs] erofs_fscache_register_fs+0x19c/0x240 [erofs] erofs_fc_fill_super+0x746/0xaf0 [erofs] vfs_get_super+0x7d/0x100 get_tree_nodev+0x16/0x20 erofs_fc_get_tree+0x20/0x30 [erofs] vfs_get_tree+0x24/0xb0 path_mount+0x2fa/0xa90 do_mount+0x7c/0xa0 __x64_sys_mount+0x8b/0xe0 do_syscall_64+0x30/0x60 entry_SYSCALL_64_after_hwframe+0x46/0xb0
Considering that wake_up_bit() is more selective, so fix it by using wait_on_bit() instead of wait_var_event() to wait for the freeing of relinquished volume. In addition because waitqueue_active() is used in wake_up_bit() and clear_bit() doesn't imply any memory barrier, use clear_and_wake_up_bit() to add the missing memory barrier between cursor->flags and waitqueue_active().
{
"affected": [],
"aliases": [
"CVE-2023-52982"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-03-27T17:15:45Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfscache: Use wait_on_bit() to wait for the freeing of relinquished volume\n\nThe freeing of relinquished volume will wake up the pending volume\nacquisition by using wake_up_bit(), however it is mismatched with\nwait_var_event() used in fscache_wait_on_volume_collision() and it will\nnever wake up the waiter in the wait-queue because these two functions\noperate on different wait-queues.\n\nAccording to the implementation in fscache_wait_on_volume_collision(),\nif the wake-up of pending acquisition is delayed longer than 20 seconds\n(e.g., due to the delay of on-demand fd closing), the first\nwait_var_event_timeout() will timeout and the following wait_var_event()\nwill hang forever as shown below:\n\n FS-Cache: Potential volume collision new=00000024 old=00000022\n ......\n INFO: task mount:1148 blocked for more than 122 seconds.\n Not tainted 6.1.0-rc6+ #1\n task:mount state:D stack:0 pid:1148 ppid:1\n Call Trace:\n \u003cTASK\u003e\n __schedule+0x2f6/0xb80\n schedule+0x67/0xe0\n fscache_wait_on_volume_collision.cold+0x80/0x82\n __fscache_acquire_volume+0x40d/0x4e0\n erofs_fscache_register_volume+0x51/0xe0 [erofs]\n erofs_fscache_register_fs+0x19c/0x240 [erofs]\n erofs_fc_fill_super+0x746/0xaf0 [erofs]\n vfs_get_super+0x7d/0x100\n get_tree_nodev+0x16/0x20\n erofs_fc_get_tree+0x20/0x30 [erofs]\n vfs_get_tree+0x24/0xb0\n path_mount+0x2fa/0xa90\n do_mount+0x7c/0xa0\n __x64_sys_mount+0x8b/0xe0\n do_syscall_64+0x30/0x60\n entry_SYSCALL_64_after_hwframe+0x46/0xb0\n\nConsidering that wake_up_bit() is more selective, so fix it by using\nwait_on_bit() instead of wait_var_event() to wait for the freeing of\nrelinquished volume. In addition because waitqueue_active() is used in\nwake_up_bit() and clear_bit() doesn\u0027t imply any memory barrier, use\nclear_and_wake_up_bit() to add the missing memory barrier between\ncursor-\u003eflags and waitqueue_active().",
"id": "GHSA-3cvm-96rv-2mw4",
"modified": "2025-03-27T18:31:26Z",
"published": "2025-03-27T18:31:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-52982"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3be069f42a7b79d3149194f21cdf24bf23864cac"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8226e37d82f43657da34dd770e2b38f20242ada7"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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