Merge tag 'v5.13-rc4' into media_tree

Linux 5.13-rc4

* tag 'v5.13-rc4': (976 commits)
  Linux 5.13-rc4
  seccomp: Refactor notification handler to prepare for new semantics
  selftests: kvm: fix overlapping addresses in memslot_perf_test
  KVM: X86: Kill off ctxt->ud
  KVM: X86: Fix warning caused by stale emulation context
  KVM: X86: Use kvm_get_linear_rip() in single-step and #DB/#BP interception
  Documentation: seccomp: Fix user notification documentation
  MAINTAINERS: adjust to removing i2c designware platform data
  perf vendor events powerpc: Fix eventcode of power10 JSON events
  Revert "serial: 8250: 8250_omap: Fix possible interrupt storm"
  i2c: s3c2410: fix possible NULL pointer deref on read message after write
  i2c: mediatek: Disable i2c start_en and clear intr_stat brfore reset
  perf stat: Fix error check for bpf_program__attach
  cifs: change format of CIFS_FULL_KEY_DUMP ioctl
  i2c: i801: Don't generate an interrupt on bus reset
  i2c: mpc: implement erratum A-004447 workaround
  powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P1010 i2c controllers
  powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P2041 i2c controllers
  dt-bindings: i2c: mpc: Add fsl,i2c-erratum-a004447 flag
  i2c: busses: i2c-stm32f4: Remove incorrectly placed ' ' from function name
  ...

1 files changed, 19 insertions, 16 deletions

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 544773970dbc..73443498d88f 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -692,38 +692,41 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
 	return -EINVAL;
 }
 
-/* Per-cpu temp buffers which can be used by printf-like helpers for %s or %p
+/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
+ * arguments representation.
  */
-#define MAX_PRINTF_BUF_LEN	512
+#define MAX_BPRINTF_BUF_LEN	512
 
-struct bpf_printf_buf {
-	char tmp_buf[MAX_PRINTF_BUF_LEN];
+/* Support executing three nested bprintf helper calls on a given CPU */
+#define MAX_BPRINTF_NEST_LEVEL	3
+struct bpf_bprintf_buffers {
+	char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
 };
-static DEFINE_PER_CPU(struct bpf_printf_buf, bpf_printf_buf);
-static DEFINE_PER_CPU(int, bpf_printf_buf_used);
+static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
+static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
 
 static int try_get_fmt_tmp_buf(char **tmp_buf)
 {
-	struct bpf_printf_buf *bufs;
-	int used;
+	struct bpf_bprintf_buffers *bufs;
+	int nest_level;
 
 	preempt_disable();
-	used = this_cpu_inc_return(bpf_printf_buf_used);
-	if (WARN_ON_ONCE(used > 1)) {
-		this_cpu_dec(bpf_printf_buf_used);
+	nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
+	if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
+		this_cpu_dec(bpf_bprintf_nest_level);
 		preempt_enable();
 		return -EBUSY;
 	}
-	bufs = this_cpu_ptr(&bpf_printf_buf);
-	*tmp_buf = bufs->tmp_buf;
+	bufs = this_cpu_ptr(&bpf_bprintf_bufs);
+	*tmp_buf = bufs->tmp_bufs[nest_level - 1];
 
 	return 0;
 }
 
 void bpf_bprintf_cleanup(void)
 {
-	if (this_cpu_read(bpf_printf_buf_used)) {
-		this_cpu_dec(bpf_printf_buf_used);
+	if (this_cpu_read(bpf_bprintf_nest_level)) {
+		this_cpu_dec(bpf_bprintf_nest_level);
 		preempt_enable();
 	}
 }
@@ -760,7 +763,7 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 		if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
 			return -EBUSY;
 
-		tmp_buf_end = tmp_buf + MAX_PRINTF_BUF_LEN;
+		tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
 		*bin_args = (u32 *)tmp_buf;
 	}