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charset=us-ascii Content-Disposition: inline In-Reply-To: <20241217142032.55793-1-acarmina@redhat.com> X-Rspamd-Server: rspam05 X-Stat-Signature: m549e4t685bpiutakxwdxujbntqjipfc X-Rspamd-Queue-Id: 9FC1C40017 X-Rspam-User: X-HE-Tag: 1734627284-950068 X-HE-Meta: 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 DGm9jRkN 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Dec 17, 2024 at 02:20:33PM +0000, Alessandro Carminati wrote: > Address a bug in the kernel that triggers a "sleeping function called from > invalid context" warning when /sys/kernel/debug/kmemleak is printed under > specific conditions: > - CONFIG_PREEMPT_RT=y > - Set SELinux as the LSM for the system > - Set kptr_restrict to 1 > - kmemleak buffer contains at least one item > > BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 > in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 136, name: cat > preempt_count: 1, expected: 0 > RCU nest depth: 2, expected: 2 > 6 locks held by cat/136: > #0: ffff32e64bcbf950 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb8/0xe30 > #1: ffffafe6aaa9dea0 (scan_mutex){+.+.}-{3:3}, at: kmemleak_seq_start+0x34/0x128 > #3: ffff32e6546b1cd0 (&object->lock){....}-{2:2}, at: kmemleak_seq_show+0x3c/0x1e0 > #4: ffffafe6aa8d8560 (rcu_read_lock){....}-{1:2}, at: has_ns_capability_noaudit+0x8/0x1b0 > #5: ffffafe6aabbc0f8 (notif_lock){+.+.}-{2:2}, at: avc_compute_av+0xc4/0x3d0 > irq event stamp: 136660 > hardirqs last enabled at (136659): [] _raw_spin_unlock_irqrestore+0xa8/0xd8 > hardirqs last disabled at (136660): [] _raw_spin_lock_irqsave+0x8c/0xb0 > softirqs last enabled at (0): [] copy_process+0x11d8/0x3df8 > softirqs last disabled at (0): [<0000000000000000>] 0x0 > Preemption disabled at: > [] kmemleak_seq_show+0x3c/0x1e0 > CPU: 1 UID: 0 PID: 136 Comm: cat Tainted: G E 6.11.0-rt7+ #34 > Tainted: [E]=UNSIGNED_MODULE > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace+0xa0/0x128 > show_stack+0x1c/0x30 > dump_stack_lvl+0xe8/0x198 > dump_stack+0x18/0x20 > rt_spin_lock+0x8c/0x1a8 > avc_perm_nonode+0xa0/0x150 > cred_has_capability.isra.0+0x118/0x218 > selinux_capable+0x50/0x80 > security_capable+0x7c/0xd0 > has_ns_capability_noaudit+0x94/0x1b0 > has_capability_noaudit+0x20/0x30 > restricted_pointer+0x21c/0x4b0 > pointer+0x298/0x760 > vsnprintf+0x330/0xf70 > seq_printf+0x178/0x218 > print_unreferenced+0x1a4/0x2d0 > kmemleak_seq_show+0xd0/0x1e0 > seq_read_iter+0x354/0xe30 > seq_read+0x250/0x378 > full_proxy_read+0xd8/0x148 > vfs_read+0x190/0x918 > ksys_read+0xf0/0x1e0 > __arm64_sys_read+0x70/0xa8 > invoke_syscall.constprop.0+0xd4/0x1d8 > el0_svc+0x50/0x158 > el0t_64_sync+0x17c/0x180 > > %pS and %pK, in the same back trace line, are redundant, and %pS can void > %pK service in certain contexts. > > %pS alone already provides the necessary information, and if it cannot > resolve the symbol, it falls back to printing the raw address voiding > the original intent behind the %pK. > > Additionally, %pK requires a privilege check CAP_SYSLOG enforced through > the LSM, which can trigger a "sleeping function called from invalid > context" warning under RT_PREEMPT kernels when the check occurs in an > atomic context. This issue may also affect other LSMs. > > This change avoids the unnecessary privilege check and resolves the > sleeping function warning without any loss of information. > > Signed-off-by: Alessandro Carminati Acked-by: Catalin Marinas